Miniaturized electronic systems with wireless power and near-field communication capabilities

ABSTRACT

The invention provides systems and methods for tissue-mounted electronics and photonics. Devices of some embodiments of the invention implement high performance, and optionally flexible, device components having miniaturized formats in device architectures that minimize adverse physical effects to tissue and/or reduce interfacial stresses when mounted on tissue surfaces. In some embodiments, the invention provides complementary tissue mounting strategies providing for mechanically robust and/or long term integration of the present devices, for example, via mounting on tissue surfaces that are not subject to rapid growth or exfoliation processes such as the fingernail, toenail, tooth or earlobe. Devices of the invention are versatile and support a broad range of applications for sensing, actuating and communication including applications for near field communication, for example, for password authentication, electronic transactions and biometric sensing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application under 35 U.S.C. §371 of International Application No. PCT/US2016/035336, filed Jun. 1,2016, which claims the benefit of priority from U.S. Provisional PatentApplication No. 62/169,308 filed Jun. 1, 2015, U.S. Provisional PatentApplication No. 62/169,983 filed Jun. 2, 2015, U.S. ProvisionalApplication No. 62/218,345 filed Sep. 14, 2015, and U.S. ProvisionalApplication No. 62/218,321 filed Sep. 14, 2015, each of which is herebyincorporated by reference in its entirety to the extent not inconsistentherewith.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF INVENTION

Wearable electronics and photonics are a class of systems with potentialto broadly impact a range of technologies, industries and consumerproducts. Advances in wearable systems are driven, in part, bydevelopment of new materials and device architectures providing for newfunctionalities implemented using device form factors compatible withthe body. Wearable consumer products are available, for example, thatexploit small and portable electronic and/or photonic systems providedin body mounted form factors, such as systems building off ofconventional body worn devices such as eye glasses, wrist bands, footware, etc. New device platforms are also under development to extend therange of wearable technology applications including smart textiles andstretchable/flexible electronic systems incorporating advancedelectronic and photonic functionality in spatially complaint formfactors compatible with low power operation, wireless communication andnovel integration schemes for interfacing with the body. [See, e.g., Kimet al., Annu. Rev. Biomed. Eng. 2012.14; 113-128; Windmiller, et al.,Electroanalysis; 2013, 25, 1, 29-46; Zeng et al., Adv. Mater., 2014, 26,5310-5336; Ahn et al., J Phys. D: Appl. Phys., 2012, 45, 103001.]

Tissue mounted systems represent one class of wearable systemssupporting diverse applications in healthcare, sensing, motionrecognition and communication. Recent advances in epidermal electronics,for example, provide a class of skin-mounted electronic and/oroptoelectronic systems provided in physical formats enabling intimatecontact with the skin. [See, e.g., US Publication No. 2013/0041235.]Epidermal electronic systems combine high performance stretchable and/orultrathin functional materials with soft elastic substrates implementedin device geometries useful for establishing and maintaining conformalcontact with the soft, curvilinear and time varying surface of the skin.A number of sensing modalities have been demonstrated using thisplatform including physiological monitoring (e.g., temperature, thermaltransport, hydration state, etc.) and transduction of chemicalinformation, for example, in connection with the characterization ofbodily fluids (e.g., pH, salt composition, etc.). [See, e.g., Huang etal., Small, 2014, 10 (15) 3083-3090; Gao, et al., Nature Communications,2014, 5, 4938.]

Despite considerable advances in tissue mounted systems a number ofchallenges remain in the development of certain applications for thistechnology. First, conformal integration of these systems on someclasses of tissue, such as the epidermis, can adversely impact thephysiological state and/or chemical condition of the tissue, for exampleresulting in unwanted irritation and/or immune response. Tissue mountedsystems can also influence the exchange of heat, fluid and/or gas at themounting site, thereby having the potential to interfere withphysiological and chemical characterization of tissue. Further, longterm, reliable integration remains a challenge for some tissue typessuch as tissues characterized by rapid rates of growth, fluid exchangeand/or exfoliation.

It will be appreciated from the foregoing that tissue mounted electronicand photonic systems are needed to support the emerging applications inwearable electronics. Tissue mounted systems and methods are needed thatare capable of robust and intimate integration without substantialdelamination. Tissue mounted systems and methods are needed that arecapable of providing good electronic and photonic performance in amanner not adversely impacting the tissue at the mounting site. Inaddition, tissue mounted systems are needed that are compatible withefficient manufacturing to enable cost effective implementation for arange of applications.

SUMMARY OF THE INVENTION

The invention provides systems and methods for tissue-mountedelectronics and photonics. Devices of some embodiments of the inventionimplement high performance, and optionally flexible, device componentshaving miniaturized formats in device architectures that minimizeadverse physical effects to tissue and/or reduce interfacial stresseswhen mounted on tissue surfaces. In some embodiments, the inventionprovides complementary tissue mounting strategies providing formechanically robust and/or long term integration of the present devices,for example, via mounting on tissue surfaces that are not subject torapid growth or exfoliation processes such as the fingernail, toenail,tooth or earlobe. Devices of the invention are versatile and support abroad range of applications for sensing, actuating and communicationincluding applications for near field communication, for example, forpassword authentication, electronic transactions and biometric sensing.

In one aspect, the invention provides a tissue mounted electronicsystem, the system comprising: (i) a substrate having an inner surfaceand an outer surface; and (ii) an electronic device comprising one ormore inorganic and/or organic components supported by the outer surfaceof the substrate; wherein the electronic device has a thickness lessthan or equal to 5 millimeters, optionally less than 1 millimeter, andhas lateral dimensions small enough to provide long-term conformalintegration via direct or indirect contact with the tissue withoutsubstantial delamination. As used herein, the expression “long-termconformal integration” refers to the capability of the present systemsto establish and maintain conformal contact with a tissue surface for atleast 3 hours, optionally at least 1 day or at least 1 month, withoutundergoing delamination or other degradation sufficient to impairelectronic or photonic performance. Miniaturized thickness and lateraldimensions are significant in some embodiments for enabling long termconformal integration, for example, wherein the electronic device ischaracterized by a maximum thickness less than 2 mm, optionally lessthan 125 micron, less than 0.1 micron or less than 0.05 micron, and/orwherein the electronic device is characterized by an area of less than 2cm², optionally less than 0.5 cm² or less than 0.1 cm². In an embodimentof this aspect, the electronic system is directly supported by and inphysical contact with the tissue or indirectly supported by the tissue,for example, via one or more intermediate components provided in betweenthe system and the tissue.

In another aspect, the invention provides a tissue mounted electronicsystem, the system comprising: (i) a substrate having an inner surfaceand an outer surface; and (ii) an electronic device comprising one ormore inorganic components, organic components or a combination ofinorganic and organic components supported by the outer surface of thesubstrate; wherein the electronic device has a thickness less than orequal to 10 millimeters, optionally less than 5 millimeters or 1millimeter, and has lateral dimensions small enough to provide conformalintegration with the tissue without inflammation or immune response ofthe tissue. As used herein, the expression “conformal integration withthe tissue without inflammation or immune response” refers to thecapability of the present systems to establish conformal contact with atissue surface without causing an observable inflammation or immuneresponse from the tissue at the mounting site. Miniaturized thicknessand lateral dimensions are significant in some embodiments for enablingconformal integration with the tissue without inflammation or immuneresponse, for example, wherein the electronic device is characterized bya maximum thickness less than 2 mm, optionally less than 125 microns,less than 0.1 micron or less than 0.05 micron, and/or wherein theelectronic device is characterized by an area of less than 2 cm²,optionally less than 0.5 cm² or less than 0.1 cm². In an embodiment ofthis aspect, the electronic system is directly supported by and inphysical contact with the tissue or indirectly supported by the tissue,for example, via one or more intermediate components provided in betweenthe system and the tissue.

In another aspect, the invention provides a tissue mounted electronicsystem, the system comprising: (i) a substrate having an inner surfaceand an outer surface; and (ii) an electronic device comprising one ormore inorganic components, organic components or combination ofinorganic and organic components supported by the outer surface of thesubstrate; wherein the electronic device has a thickness less than orequal to 10 millimeters, optionally less than 5 millimeters or 1millimeter, and has lateral dimensions small enough to provide conformalintegration with the tissue without substantially changing the exchangeof heat and fluids from the tissue surface upon which the system ismounted. As used herein, the expression “conformal integration with thetissue without substantially changing the exchange of heat and fluids”refers to the capability of the present systems to establish conformalcontact with a tissue surface without changing the amount of heat andfluids absorbed or released from the tissue surface at the mounting siteby a factor greater than 75%, optionally greater than 25%, relative tothe tissue surface without the mounted device. Miniaturized thicknessand lateral dimensions are significant in some embodiments for enablingconformal integration with the tissue without substantially changing theexchange of heat and fluids, for example, wherein the electronic deviceis characterized by a maximum thickness less than 2 mm, optionally lessthan 125 microns, less than 0.1 micron or less than 0.05 micron, and/orwherein the electronic device is characterized by an area of less than 2cm², optionally less than 0.5 cm² or less than 0.1 cm². In an embodimentof this aspect, the electronic system is directly supported by and inphysical contact with the tissue or indirectly supported by the tissue,for example, via one or more intermediate components provided in betweenthe system and the tissue.

In another aspect, the invention provides a tissue mounted electronicsystem, the system comprising: (i) a substrate having an inner surfaceand an outer surface; and (ii) an electronic device comprising one ormore inorganic components, organic components or combination ofinorganic and organic components supported by the outer surface of thesubstrate; wherein the electronic device is capable of establishingconformal integration with the tissue, and wherein the electronic deviceundergoes a transformation upon an external stimulus or an internalstimulus; wherein the transformation provides a change in function ofthe system from a first condition to a second condition. Systems of thisaspect may be compatible with a range of external and/or internalstimuli, including movement of the system, tempering with the system, aphysical, chemical or electromagnetic change of the system, change in ameasured signal or property, change in an ambient parameter andcombinations of these. In an embodiment, the transformation provides thechange in function of the device from a first condition of operabilityto a second condition of inoperability. In an embodiment, thetransformation is induced upon removal or attempted removal of thesystem from a mounting position on the tissue. In an embodiment, thetransformation is induced by a physical change, a chemical change, athermal change or electromagnetic change of the system or a componentthereof. In an embodiment, the transformation is induced by physicalbreakage of a component of the system (e.g., breakage of an activecomponent, breakage of an electronic interconnect, breakage of thesubstrate, breakage of a barrier layer or encapsulating layer, etc.), aphysical deformation of a component of the system (e.g. deformation ofan active component, deformation of an electronic interconnect,deformation of the substrate, etc.), a change in physical conformationof the system (e.g., change in contour, a change in curvature, etc.), orremoval of a barrier or encapsulation layer of the system, for example,such that resulting exposure to the environment induces a change. In anembodiment, the transformation is induced a change in a value of ameasured device property (e.g., state of strain, antenna property), ameasured physiological property of the tissue or subject (e.g.,temperature, pH level, glucose, pulse oximetry, heart rate, respiratoryrate, blood pressure, peripheral capillary oxygen saturation (SpO2)) ormeasured ambient property (e.g., temperature, electromagnetic radiation,etc.). In an embodiment, the transformation is induced by a positionalchange (e.g., movement of the system) or a temporal change (e.g., uponelapse of a preselected period of time). Miniaturized thickness andlateral dimensions are significant in some embodiments for enabling acapability of undergoing a transformation upon removal from a mountinglocation, for example, wherein the electronic device is characterized bya maximum thickness less than 2 mm, optionally less than 125 microns,less than 0.1 micron or less than 0.05 micron, and/or wherein theelectronic device is characterized by an area of less than 2 cm²,optionally less than 0.5 cm² or less than 0.1 cm². In an embodiment ofthis aspect, the electronic system is directly supported by and inphysical contact with the tissue or indirectly supported by the tissue,for example, via one or more intermediate components provided in betweenthe system and the tissue.

In another aspect, the invention provides a tissue mounted electronicsystem, the system comprising: (i) a substrate having an inner surfaceand an outer surface; wherein the inner surface of the substrate is forestablishing contact with a tissue surface; and (ii) an electronicdevice comprising one or more inorganic components, organic componentsor a combination of inorganic and organic components; wherein each ofthe inorganic components is supported by the outer surface andindependently positioned within 20 millimeters, optionally 16millimeters, or 10 millimeters, or 1 millimeter, of an edge of thesubstrate (e.g., perimeter edge or edge of a cut-out region positionedaway from the perimeter); wherein the tissue mounted electronic devicehas lateral dimensions less than or equal to 20 millimeters, optionallyfor some applications less than or equal to 16 millimeters, and athickness less than or equal to 5 millimeters, optionally for someapplications less than or equal to 10 millimeters. In an embodiment ofthis aspect, the electronic system is directly supported by and inphysical contact with the tissue or indirectly supported by the tissue,for example, via one or more intermediate components provided in betweenthe system and the tissue.

As used herein, the term “tissue-mounted” is intended to broadly includea class of systems that upon implementation are supported by one or moretissue surfaces. In some embodiments, upon implementation,tissue-mounted systems of the invention are supported directly by atissue surface, for example, wherein a surface of the system, such as asubstrate surface, is in physical contact with the tissue surface, suchas in conformal contact. In some embodiments, upon implementation,tissue-mounted systems of the invention are supported indirectly by atissue surface, for example, wherein a surface of the system, such as asubstrate surface, is in physical contact with an intermediatestructure, such as an integration platform, provided between the tissuesurface and the tissue-mounted system. A tissue mounted system may becoupled to the body by a wide variety of intermediate structuressupported by the body including manufactured materials and non-naturalmaterials. In some embodiments, for example, a tissue mounted system maybe directly or indirectly coupled to the body by faux nails (i.e., falsefinger nails), teeth, clothing (buttons, tags, woven material, etc),jewelry (e.g., rings, bracelets, necklaces, wrist watches, piercings,etc.), body-enhancements, glasses, gloves, nail polish and the like.

Conformal integration refers to the ability of the present systems to beprovided to a tissue in a manner that the device spatially conforms atan interface between the system and the tissue or at the interface withan intermediate structure provided between the system and tissuesurface. Conformal integration may be via direct or indirect contactwith a tissue surface. Tissue mounted systems of the invention may beprovided in direct conformal integration, wherein the system itselfestablishes conformal contact with the tissue surface. Tissue mountedsystems of the invention may be provided in indirect conformalintegration, wherein the system is provided on an intermediate structureprovided in conformal contact with the tissue surface, such as aprosthetic, adhesive tape, faux nails (i.e., false finger nails),clothing (buttons, tags, woven material, etc), jewelry (e.g., rings,bracelets, necklaces, wrist watches, piercings, etc.),body-enhancements, glasses, gloves, nail polish and the like.

In some embodiments, for example, the system has lateral dimensionsselected from the range of 5 mm to 20 mm. In some embodiments, forexample, the system has thickness dimensions selected from the range of0.125 mm to 5 mm, or 0.005 mm to 5 mm. In some embodiments, for example,the system is characterized by a footprint/contact area of 10 mm² to 500mm², or 20 mm² to 350 mm², or 30 mm² to 150 mm², in some embodiments thesystem is characterized by a footprint/contact area greater than 25 mm²or greater than 20 mm². In some embodiments, for example, the system ischaracterized by an areal mass density of 0.1 mg cm⁻² to 100 mg cm⁻². Insome embodiments, for example, the system has a tapered thickness fromthe center to outer edge. In some embodiments, a taper of not less than5 degrees, or not less than 10 degrees, from the center of the system tothe outer edge reduces or prevents delamination. In some embodiments,the system is symmetrically or asymmetrically tapered from the center tothe outer edges. In some embodiments, for example, the system has ashape selected from the group consisting of elliptical, rectangular,circular, serpentine and irregular shapes. In some embodiments, forexample, the system is characterized by component lateral dimensionsselected from 4 mm to 16 mm. In some embodiments, for example, thesystem comprises Sheldahl Novaclad® adhesiveless laminate made with 18μm copper×12 μm polyimide film×18 μm copper.

In some embodiments, the overall system geometry is designed to reduceor prevent delamination, for example, via having a tapered geometry. Inan embodiment, for example, a portion of, or all, intersecting outersurfaces are joined radially at an angle to reduced or preventdelamination. In an embodiment, for example, the system is characterizedby a gradual reduction of thickness in a range equal to or less than thecenter of the device to outer surface to reduce or prevent delamination.In an embodiment, for example, a thickness at an edge, such as an outeredge of the system or an edge of an aperture of the system, is at least2 times, or at least 5 times, or at least 10 times, less than athickness at a center (or mid-point between edges) of a system. In anembodiment, a thickness of the overall system decreases substantiallyasymptotically from a mid-point of the system to an edge, such as anouter edge of the system or an edge of an aperture of the system.

In some embodiments, the present systems are waterproof, for example, byencapsulation or packaging, with a biopolymer, a thermoset polymer, arubber, an adhesive tape, plastic or any combination of these. Forexample, in embodiments, the system comprises an encapsulation layer orother waterproofing structure comprising polyimide, conformal Q, vinyl,acrylic, polydimethylsiloxane (PDMS), polyurethane, vinyl, polystyrene,polymethyl methacrylate (PMMA) or polycarbonate.

In some embodiments, the present systems incorporate an easy peel tab tofacilitate deployment onto a tissue surface, for example, that caneasily be discarded after mounting.

In an embodiment, the inner surface of the substrate conforms to thecurvature of a tissue surface. In embodiments, the inorganic and/ororganic components are selected from inorganic and/or organicsemiconductor components, metallic conductor components and combinationsof inorganic semiconductor components and metallic conductor components.In an embodiment, for example, each of the inorganic components isindependently positioned within 10 millimeters, optionally within 1millimeter, of an edge of the perimeter of the substrate. In anembodiment, each of the inorganic components is independently positionedwithin 10 millimeters, and in some embodiments less; e.g. optionallywithin 1 millimeter, of an edge of an aperture in the substrate. In anembodiment, each of the inorganic components is independentlycharacterized by a shortest distance to an edge of the substrate,wherein an average of the shortest distances for the inorganiccomponents is equal to or less than 10 millimeters, optionally equal toor less than 1 millimeter.

Systems and methods of some aspects of the invention exploit overallsize miniaturization to achieve a mechanically robust interface with atissue surface without generating stresses or strains adverselyimpacting performance and/or to minimize adverse physical effects totissue. In embodiments, for example, the tissue mounted electronicsystem has a lateral area footprint less than or equal to 500 mm²,optionally less than or equal to 315 mm², or selected from the range of1 mm² to 500 mm² and optionally selected from the range of 1 mm² to 315mm². In an embodiment, the ratio of a lateral area foot print of thetissue mounted electronic system to the area of the tissue is greaterthan or equal to 0.1. In an embodiment, the tissue mounted electronicsystem has an areal mass density selected from the range of 1 mg cm⁻² to100 mg cm⁻². In embodiments, the tissue mounted electronic system has anaverage thickness selected from the range of 5 microns to 5 millimeters,optionally 12 microns to 1 millimeter, optionally 50 microns to 90microns, or, for example, greater than 50 microns. In an embodiment, thetissue mounted electronic system has an overall maximum thickness lessthan 0.1 mm and at least one region having a thickness selected from therange of 0.05 mm to 0.09 mm. For example, a region of the tissue mountedelectronic system comprising a relatively thick component, such as anNFC chip or an LED, may provide a thickness less than 0.1 mm and aregion of the tissue mounted electronic system comprising a relativelythin component, such as only substrate, may provide a thickness selectedfrom the range of 0.05 mm to 0.09 mm, or a thickness of less than 0.09mm, or less than 0.07 mm.

Systems and methods of some aspects of the invention integrate thin,flexible functional components and substrates to provide sufficientmechanical compliance to achieve a conformal interface at the mountingsite for a tissue surface. Advantages of mechanically flexible systemsof the invention include the ability to conform to complex contouredtissue surfaces and/or tissue surfaces that are dynamic with respect totime. Alternatively, the invention also includes rigid systemsintegrating rigid functional components and/or substrates, for example,for integration with tissue types having compatible physical properties,such as the fingernail, tooth or toenail. Advantages of mechanicallyrigid systems of the invention include providing high functionalitysystems, where thin, mechanically flexible construction might representa disadvantage, in terms of potential damage during manipulation.

In embodiments, the tissue mounted electronic system has an averagemodulus selected from the range of 10 kPa to 100 GPa, or greater than 10kPa, optionally greater than 100 MPa. In embodiments, the tissue mountedelectronic system has a flexural rigidity selected from the range of 0.1nN m to 1 N m. In an embodiment, the tissue mounted electronic systemhas a net bending stiffness of greater than 0.1 nN m, optionally forsome applications greater than 10 nN m, and optionally for someapplications greater than 1000 nN m. In some embodiments, for example,one or more mechanical properties of the device, such as averagemodulus, flexural rigidity or bending stiffness, are matched toproperties of the tissue at the mounting site; e.g., within a factor of5. In embodiments, for example, the system is rigid and in a fixed shapeto conform to a tissue surface, such as a curved or contoured shape thatmatches the tissue surface, e.g., matches the curvature of thefingernail. In embodiments, the tissue mounted electronic system has anadhesion strength selected from the range of 1 N/25 mm to 50 N/25 mm, orthe tissue mounted electronic system has an adhesion strength greaterthan 50 N/25 mm, or greater than 60 N/25 mm. In some embodiments, peeladhesion can be tuned for specific applications after 20 minutes at roomtemperature.

Systems of the invention include multilayer devices, for example,wherein functional layers having electronically and/oroptoelectronically functional device components are separated from eachother by structural layers, such as electrically insulating orsupporting layers or coatings. In embodiments, the tissue mountedelectronic system has a multilayer geometry comprising a plurality offunctional layers, supporting layers, encapsulating layers, planarizinglayers or any combination of these. In embodiments, the tissue mountedelectronic system has a shape selected from the group consisting ofelliptical, rectangular, circular, serpentine and/or irregular. In anembodiment, the shape is characterized by an aspect ratio of a lateraldimension to thickness less than 10,000 or optionally for someembodiments selected from the range of 5000 to 3.

Substrates having a range of physical and chemical properties are usefulin the systems and methods of the present invention. The inventionincludes substrates having functionality as an electrical insulator, anoptically transparent layer, an optical filter and/or a mechanicallysupporting layer. In embodiments, the inner surface of the substrate hasan area for establishing the conformal contact with the tissue surfaceless than or equal to 315 mm², or selected from the range of 19 mm² to315 mm². In an embodiment, the substrate has a perforated geometryincluding a plurality of apertures extending through the substrate. Inan embodiment, the substrate is discontinuous. In an embodiment, theapertures allow passage of gas and fluid from the tissue through thedevice, in some embodiments, the apertures allow transport of fluid awayfrom the tissue surface. In an embodiment, each of the apertures isindependently characterized by lateral dimensions selected from therange of 12 microns to 5 millimeters, or 25 microns to 1 millimeter, or50 microns to 500 microns. In an embodiment, perforations aredistributed in the substrate with a pitch selected from the range of 4mm to 0.2 mm, or 2 mm to 0.5 mm. In an embodiment, the perforations areopenings, such as circular openings, having average diameters greaterthan 0.1 mm and less than 2 mm, or greater than 0.2 mm and less than 1mm. In an embodiment, the substrate has an areal density of theapertures selected from the range of one per cm² to one hundred per cm².In an embodiment, the apertures are provided in a substantiallyspatially uniform distribution across the substrate. In an embodiment,the apertures provide an overall mesh geometry of the substrate. In anembodiment, the apertures provide a porosity of the substrate equal toor greater than 0.01%, optionally for some embodiments equal to orgreater than 0.1%, or equal to or greater than 1%, or equal to orgreater than 10%. In an embodiment, a perforated or discontinuoussubstrate comprises at least 0.01% open area, or at least 0.1% openarea, or at least 0.5% open area, or at least 1% open area, or at least5% open area, or at least 10% open area. In an embodiment, each of theapertures is independently characterized by a cross sectional areaselected from the range of 100 μm² to 1 cm², or 200 μm² to 1 mm², or 500μm² to 0.5 mm².

In embodiments, the substrate is a flexible substrate or a stretchablesubstrate. In an embodiment, the substrate is characterized by anaverage modulus selected from the range of 10 kPa to 100 GPa, or greaterthan 10 kPa, optionally for some applications greater than 10 kP. In anembodiment, the substrate is characterized by an average thicknessselected from the range of 12 microns to 5 millimeters, 25 microns to 1millimeter, or 50 microns to 90 microns, and in some embodiments,greater than 500 microns, optionally for some embodiments, greater than1000 microns.

In an embodiment, the substrate comprises one or more thin films,coatings or both. For example, in some embodiments, a coating or thinfilm is provided directly on the electronic device or component thereof,and in some embodiments, in direct physical contact. In someembodiments, however, the coating or thin film is provided on anintermediate structure positioned between the electronic device and thecoating or film. In embodiments, the substrate comprises an inorganicpolymer, an organic polymer, a plastic, an elastomer, a biopolymer, athermoset polymer, a rubber, an adhesive tape or any combination ofthese. For example, in embodiments, the substrate comprises polyimidepolydimethylsiloxane (PDMS), polyurethane, cellulose paper, cellulosesponge, polyurethane sponge, polyvinyl alcohol sponge, silicone sponge,polystyrene, polymethyl methacrylate (PMMA) or polycarbonate.

A range of functional electronic device components and deviceintegration strategies are compatible with the present methods andsystems, thereby supporting expansive applications in wearableelectronics. In an embodiment, for example, the system further comprisesone or more encapsulating layers or coatings for encapsulating theelectronic device. In embodiments, the electronic device is a rigiddevice, a semi-rigid device, a flexible electronic device or astretchable electronic device. In embodiments, for example, each of theone or more inorganic or organic components independently comprises oneor more thin films, nanoribbons, microribbons, nanomembranes ormicromembranes. In an embodiment, the one or more inorganic or organiccomponents independently comprise a single crystalline inorganicsemiconductor material.

In an embodiment, for example, the one or more inorganic or organiccomponents independently have a thickness selected from the range of 5microns to 5000 microns, optionally for some applications 50 microns to100000 microns, optionally for some applications the range of 50 micronsto 2000 microns. In an embodiment, for example, the one or moreinorganic or organic components independently have a thickness greaterthan 5 microns and optionally for some embodiments a thickness greaterthan 50 microns. In an embodiment, the one or more inorganic or organiccomponents are independently characterized by a curved geometry, forexample, a bent, coiled, interleaved or serpentine geometry. In anembodiment, the one or more inorganic or organic components arecharacterized by one or more island and bridge structures.

In embodiments, the electronic device has a multilayer geometrycomprising a plurality of functional layers, barrier layers, supportinglayers and encapsulating layers. In an embodiment, the electronic deviceis provided proximate to a neutral mechanical surface of the system. Inan embodiment, for example, the electronic device comprises one or moresensors or a component thereof, for example, sensors selected from thegroup consisting of an optical sensor, an electrochemical sensor, achemical sensor, a mechanical sensor, a pressure sensor, an electricalsensor, a magnetic sensor, a strain sensor, a temperature sensor, a heatsensor, a humidity sensor, a motion sensor (e.g., accelerometer,gyroscope), a color sensor (colorimeter, spectrometer), an acousticsensor, a capacitive sensor, an impedance sensor, a biological sensor,an electrocardiography sensor, an electromyography sensor, anelectroencephalography sensor, an electrophysiological sensor, aphotodetector, a particle sensor, a gas sensor, an air pollution sensor,a radiation sensor, an environmental sensor and an imaging device.

In an embodiment, the electronic device comprises one or more actuatorsor a component thereof, for example, actuators or a component thereofgenerating electromagnetic radiation, optical radiation, acousticenergy, an electric field, a magnetic field, heat, a RF signal, avoltage, a chemical change or a biological change. In embodiments, theone or more actuators or a component thereof are selected from the groupconsisting of a heater, an optical source, an electrode, an acousticactuator, a mechanical actuator, a microfluidic system, a MEMS system, aNEMS system, a piezoelectric actuator, an inductive coil, a reservoircontaining a chemical agent capable of causing a chemical change or abiological change, a laser, and a light emitting diode.

In embodiments, the electronic device comprises one or more energystorage systems or a component thereof, for example, energy storagesystems or components thereof selected from the group consisting of anelectrochemical cell, a fuel cell, a photovoltaic cell, a wireless powercoil, a thermoelectric energy harvester, a capacitor, a super capacitor,a primary battery, a secondary battery and a piezoelectric energyharvester.

In embodiments, the electronic device comprises one or morecommunication systems or a component thereof, for example, communicationsystems or components thereof selected from the group consisting of atransmitter, a receiver, a transceiver, an antenna, and a near fieldcommunication device.

In embodiments, the electronic device comprises one or more coils, forexample, inductive coils or near-field communication coils. In anembodiment, each of the near-field communication coils independently hasa diameter selected from the range of 50 microns to 20 millimeters. Inan embodiment, for example, each of the near-field communication coilsindependently has an average thickness selected from the range of 1micron to 5 millimeters, 1 micron to 500 microns, 1 micron to 100microns, 5 microns to 90 microns, or 50 microns to 90 microns. In anembodiment, for example, each of the near-field communication coilschanges by less than 50%, and optionally changes by less than 20%, uponchanging from a planar configuration to a bent configurationcharacterized by a radius of curvature selected from the range of 1 mmto 20 mm. In an embodiment, each of the near-field communication coilsis characterized by a Q factor greater than or equal to 3. In anembodiment, the one or more coils are at least partially encapsulated bythe substrate or one or more encapsulation layers. In embodiments, forexample, the one or more coils have a geometry selected from the groupconsisting of an annulus or an elliptical annulus. In an embodiment, thetissue mounted system of the invention comprises at least two layeredcoils, wherein the coils are separated by a dielectric layer.

In some embodiments, the transfer of information to and/or from thesystem is done wirelessly, for example, through ISO standards such asISO14443 for proximity contanctless cards, ISO15693 for vicinitycontactless cards, ISO18000 set of standards for RFIDs and EPC globalClass 1 Gen 2 (=18000-6C).

In an aspect, the tissue mounted system of the invention furthercomprises a mounting platform to provide effective integration with oneor more tissue surfaces. In some embodiments, for example, the mountingplatform has an external surface for establishing contact with a surfaceof said tissue and an internal surface for supporting said electronicdevice and substrate. In an embodiment, the mounting platform is thesubstrate component of the system itself. In an embodiment, saidmounting platform is for establishing conformal contact with said tissuesurface, such as establishing conformal contact with a surface of afingernail. The invention includes mounting platform components that arerigid or flexible. In an embodiment, the mounting platform is aprosthetic. In an embodiment, the mounting platform is an adhesive tape.In an embodiment, the mounting platform is a false fingernail.

In some embodiments, the system further comprises one or more LEDcomponents, for example, to provide an indication of devicefunctionality or for aesthetics. In an embodiment, for example, thesystem includes one or more LED components designed to remain on afterbeing removed from a reader. In an embodiment, for example, the systemis incorporated in or encapsulated by a faux nail or nail covering, suchas nail polish. In an embodiment, for example, the system includes coverlayers or packaging to be made to match tissue in shape and color, forexample, for a camouflage function.

In some embodiments, for privacy, the invention has a devoted chip thatstores an encrypted identification number that is unique to eachindividual device. In addition, the chip has action-specific securitycodes that change constantly. The encrypted device number helps keeppatient health-care information private. Clinicians, hospitalmanagement, and insurance providers are the only users with access tothe information. In case of emergency, hospital personnel can quicklylocate missing patients and or observe patient vital signs.

The systems and methods disclosed herein are versatile and perform awide array of biological functions for a diverse range of tissue types.In addition, the present invention may be used to communicate to avariety of external electronic devices. In an embodiment, for example,the inner surface of the substrate is capable of establishing conformalcontact with the tissue surface comprising an external tissue. Inembodiments, the external tissue is skin, a fingernail, a toenail, atooth, hair or an ear lobe. In an embodiment, hair includes but is notlimited to hair on a wearer's head, eyebrows or body hair. Inembodiments, for example, the inner surface of the substrate is bondedto the tissue surface via an adhesive, such as an acrylic, silicone,ACP, Conformal Q, lead free solder or any combination of these. In anembodiment, the system further comprises a near field communicationdevice, for example, a near field communication device for passwordauthentication, electronic transactions or biosensing. In an embodiment,the near field communication device is for communicating with a computeror mobile electronic device.

In an aspect, the present invention is a method of sensing, actuating orcommunicating; the method comprising: (i) providing a tissue mountedelectronic system on a tissue surface; wherein the tissue mountedelectronic system comprises: (a) a substrate having an inner surface andan outer surface; and (b) an electronic device comprising one or moreinorganic components, organic components or combination of inorganic andorganic components supported by the outer surface of the substrate;wherein the electronic device has a thickness less than or equal to 5millimeters, optionally less than 10 millimeters, and has lateraldimensions small enough to provide long-term conformal integration withthe tissue without substantial delamination; and (ii) sensing, actuatingor communicating using the tissue mounted electronic system.

In an aspect, the present invention is a method of sensing, actuating orcommunicating; the method comprising: (i) providing a tissue mountedelectronic system on a tissue surface; wherein the tissue mountedelectronic system comprises: (a) a substrate having an inner surface andan outer surface; and (b) an electronic device comprising one or moreinorganic components, organic components or combination of inorganic andorganic components supported by the outer surface of the substrate;wherein the electronic device has a thickness less than or equal to 5millimeters, optionally less than 10 millimeters, and has lateraldimensions small enough to provide conformal integration with the tissuewithout substantial inflammation or immune response; and (ii) sensing,actuating or communicating using the tissue mounted electronic system.

In an aspect, the present invention is a method of sensing, actuating orcommunicating; the method comprising: (i) providing a tissue mountedelectronic system on a tissue surface; wherein the tissue mountedelectronic system comprises: (a) a substrate having an inner surface andan outer surface; and (b) an electronic device comprising one or moreinorganic components, organic components or combination of inorganic andorganic components supported by the outer surface of the substrate;wherein the electronic device has a thickness less than or equal to 5millimeters, optionally less than 1 millimeter, and has lateraldimensions small enough to provide conformal integration with the tissuewithout substantially changing the exchange of heat and fluids from thetissue surface upon which the system is mounted; and (ii) sensing,actuating or communicating using the tissue mounted electronic system.

In an aspect, the present invention is a method of sensing, actuating orcommunicating; the method comprising: (i) providing a tissue mountedelectronic system on a tissue surface; wherein the tissue mountedelectronic system comprises: (a) a substrate having an inner surface andan outer surface; and (b) an electronic device comprising one or moreinorganic components, organic components or combination of inorganic andorganic components supported by the outer surface of the substrate;wherein the electronic device has a thickness less than or equal to 5millimeters, optionally less than 10 millimeters, and has lateraldimensions small enough to provide conformal integration with the tissuein a manner such that it is rendered functionally inoperable uponremoval from the tissue; and (ii) sensing, actuating or communicatingusing the tissue mounted electronic system.

In an aspect, the present invention is a method of sensing, actuating orcommunicating; the method comprising: (i) providing a tissue mountedelectronic system on a tissue surface; wherein the tissue mountedelectronic system comprises: (a) a substrate having an inner surface andan outer surface; wherein the inner surface of the substrate is forestablishing contact with a tissue surface; (b) an electronic devicecomprising one or more inorganic components, organic components orcombination of inorganic and organic components supported by the outersurface and independently positioned within 10 millimeters, optionally 1millimeter, of an edge of the substrate (e.g., perimeter edge or edge ofa cut-out region positioned away from the perimeter); wherein the tissuemounted electronic device has lateral dimensions less than or equal to20 millimeters and a thickness less than or equal to 5 millimeters,optionally for some applications less than or equal to 10 millimeters;and (ii) sensing, actuating or communicating using the tissue mountedelectronic system.

The invention includes mounting strategies supportive of a range ofapplications for wearable electronics. In an embodiment, for example,the tissue surface comprises an external tissue of a subject, such as ahuman or nonhuman subject. In an embodiment, for example, the externaltissue is characterized by a growth rate less than or equal to 6 mm permonth or for some embodiments less than or equal to 0.1 mm per day. Inan embodiment, for example, the external tissue is characterized by arate of exfoliation less than or equal to once per day or for someembodiments less than or equal to 0.1 mm per day. In an embodiment, forexample, the external tissue is characterized by a modulus greater thanor equal to 10 kPa, optionally for some embodiments greater than orequal to 10 MPa. In an embodiment, for example, the external tissue ischaracterized by a bending stiffness greater than or equal to 0.1 nN m,optionally for some embodiments greater than or equal to 100 nN m orgreater than or equal to 1000 nN m. In an embodiment, for example, thetissue surface is characterized by a radius of curvature selected fromthe range of 1 mm to 25 mm.

In an embodiment, for example, the tissue is human tissue. In anembodiment, for example, the tissue is skin, fingernail, a tooth, hairor an ear lobe of a human subject. In an embodiment, for example, thetissue is not epidermal tissue. In an embodiment, for example, thetissue is not internal tissue. In an embodiment, for example, the tissueis non-human tissue, such as tissue of a non-human animal, for examplefor livestock or veterinary applications. In an embodiment, for example,the tissue is non-human tissue, such as tissue of a plant (e.g. leavesand/or roots), for example for agricultural applications.

In an embodiment, the sensing, actuating or communicating comprisesgenerating or receiving a near field communication signal, for example,wherein the near field communication signal is received or generated bya computer or portable electronic device. In an embodiment, for example,the near field communication signal is for password authentication,electronic transactions or biosensing.

In an embodiment, for example, the sensing, actuating or communicatingcomprises sensing one or more tissue properties, such as physiological,electrophysiological, chemical, thermal or optical properties of thetissue. In an embodiment, for example, the sensing, actuating orcommunicating comprises sensing one or more physical or chemicalproperties of a biological fluid from the tissue.

In an embodiment, for example, the sensing, actuating or communicatingcomprises actuating the tissue. In an embodiment, for example, theactuating comprises electrostatically, thermally, optically,acoustically, magnetically or chemically actuating the tissue.

In an embodiment, for example, a step of sensing one or more propertiescomprises sensing a discrete, substantially instantaneous signal orsensing a cumulative signal acquired over a period of time.

In an embodiment, multiple tissue mounted systems, spatially distributedfrom one another, may provide data indicative of a spatially orspatiotemporally varying property.

In an aspect, the present invention is a method of authenticating a userto an external device; the method comprising: providing a tissue mountedelectronic system on a tissue surface; wherein the tissue mountedelectronic system comprises: a substrate having an inner surface and anouter surface; and an electronic device comprising one or more inorganiccomponents, organic components or a combination of inorganic and organiccomponents supported by the outer surface of the substrate (e.g.,perimeter edge or edge of a cut-out region positioned away from theperimeter); and communicating using the tissue mounted electronic systemto provide an authentication signal to an external device. In anembodiment, upon receiving the authentication signal the external devicegrants the user access to operate the external device. For example, theexternal device may be a computer, a phone, a gun, a pill bottle, adoor, a vehicle, a safe, a lockbox, a turnstile, a gate, an elevator ora lock.

In an aspect, the present invention is a method of making an electronicpayment; the method comprising: providing a tissue mounted electronicsystem on a tissue surface; wherein the tissue mounted electronic systemcomprises: a substrate having an inner surface and an outer surface; andan electronic device comprising one or more inorganic components,organic components or a combination of inorganic and organic componentssupported by the outer surface of the substrate (e.g., perimeter edge oredge of a cut-out region positioned away from the perimeter); andcommunicating using the tissue mounted electronic system to providepayment information to an external device.

In an aspect, the present invention is a method of ensuring usercompliance; the method comprising: providing a tissue mounted electronicsystem on a tissue surface; wherein the tissue mounted electronic systemcomprises: a substrate having an inner surface and an outer surface; andan electronic device comprising one or more inorganic components,organic components or a combination of inorganic and organic componentssupported by the outer surface of the substrate (e.g., perimeter edge oredge of a cut-out region positioned away from the perimeter); andcommunicating a signal indicative of a location and identification ofthe tissue mounted electronic system to an external device.

In an aspect, the present invention is a method of transferring digitalcontent; the method comprising: providing a tissue mounted electronicsystem on a tissue surface; wherein the tissue mounted electronic systemcomprises: a substrate having an inner surface and an outer surface; andan electronic device comprising one or more inorganic components,organic components or a combination of inorganic and organic componentssupported by the outer surface of the substrate (e.g., perimeter edge oredge of a cut-out region positioned away from the perimeter); andcommunicating a signal indicative of the digital content from the tissuemounted electronic system to an external device.

In an embodiment, the electronic device is rendered functionallyinoperable upon removal from a tissue. For example, in an embodiment,the electronic device is rendered functionally inoperable by physicalbreakage or deformation of at least a portion of a device component. Inanother embodiment, the electronic device is rendered functionallyinoperable by removal of a barrier or encapsulation layer to expose atleast a portion of a device component to an external environment.According to this embodiment, exposed device components may bephysically or chemically removed by elements in the externalenvironment. Exemplary device components that may be broken, deformed orexposed include, but are not limited to, interconnects, coils,substrates or a combination thereof. In an embodiment, the deformationcomprises a change in curvature of the system toward the inner surfaceof the substrate greater than or equal to a 4 mm radius of curvature. Inan embodiment, the deformation comprises a change in curvature of thesystem away from the inner surface of the substrate.

In an embodiment, the electronic device is rendered functionallyinoperable when a value of a measured physiological property is outsideof a threshold window. In an embodiment, the physiological property maybe selected from the group consisting of temperature, pH level, glucose,pulse oximetry, heart rate, respiratory rate, blood pressure, peripheralcapillary oxygen saturation (SpO2) and combinations thereof. Forexample, a temperature below the typical basal body temperature of awearer of a device may indicate that the device has been removed fromtissue, or a pulse or heart rate of zero may indicate that a wearer isdeceased, and the device should be rendered inoperable. Inoperabilitymay be achieved, for example, by a microprocessor of the deviceinitiating instructions that prevent transmission (e.g., of secureinformation, such as personal identifying information or paymentinformation) from the electronic device to an external device or by amicroprocessor of the electronic device initiating instructions toprovide excess power to a component of the device to electricallydestroy the component, thereby achieving functional inoperability.

In an embodiment, the electronic device is rendered functionallyinoperable after a predetermined amount of time, after being used a setnumber of times, or upon failure to properly authenticate after a setnumber of tries. For example, the electronic device may self-destruct orbecome unusable after a set period of time after being used a set numberof times, or upon failure to properly authenticate after a set number oftries. In an embodiment, the predetermined amount of time or allowableusages or authentication attempts is programmed into a microcontrollerof the electronic device and inoperability may be achieved, for example,by a microprocessor of the device initiating instructions that preventtransmission from the electronic device to an external device or by amicroprocessor of the electronic device initiating instructions toprovide excess power to a component of the device to electricallydestroy the component, thereby achieving functional inoperability.

Without wishing to be bound by any particular theory, there may bediscussion herein of beliefs or understandings of underlying principlesrelating to the devices and methods disclosed herein. It is recognizedthat regardless of the ultimate correctness of any mechanisticexplanation or hypothesis, an embodiment of the invention cannonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A. Schematic illustration of a top plan view of a tissue mountedsystem comprising a fingernail mounted NFC device.

FIG. 1B. Schematic illustration of a side exploded view of a tissuemounted system comprising a fingernail mounted NFC device.

FIG. 2. Schematic illustration and images of flexible mm-NFC deviceswith and without LEDs. (a, b) Pictures of the devices and (c) scanningelectron microscope image of the region of (b) indicated by the reddashed box. (d) Cross-sectional SEM image of one part of the coils. (e)Exploded-view schematic illustration of each layer of a device mountedon a fingernail. (f) Picture of a free-standing device held at one edgeby tweezers.

FIG. 3. Experimental and simulation results for the electromagneticproperties of flexible mm-NFC devices bent to different radii ofcurvature. (a) Top view and 3D illustrations of devices at differentcurvatures. (b) Measured phase responses of the coils as a function ofradius of curvature and (c) corresponding simulation results. (d)Measured and simulated changes in resonant frequency with radius ofcurvature. (e) Measured and simulated changes in Q factor with radius ofcurvature.

FIG. 4. Experimental and simulation results for the electromagneticproperties of mm-NFC devices with elliptical shapes. (a) Pictures ofelliptical mm-NFC devices with different eccentricities (i.e. ratios ofmajor to minor axes, b/a). (b) Measured phase responses of the coils asa function of eccentricity and (c) corresponding simulation results. (d)Measured and simulated changes in resonant frequency with b/a. (e)Measured and simulated changes in Q factor with b/a.

FIG. 5. Experimental and simulation results of the mechanical responsesof flexible mm-NFC devices to applied strain. (a) Pictures of arepresentative device mounted onto a soft silicon substrate that isundeformed (center), stretched (left) and compressed (right) byapplication of force using a mechanical stage. (b) The bottom framesshow corresponding FEA results of applied stresses. (c) Phase responsesmeasured after different numbers of cycles of uniaxial stretching (to20%)/compressing (to 20%). (d) Plot of the energy release rate with thediameter of mm-NFC device. (e) Picture of a device mounted on the skinduring a pinching mode deformation. (f) Simulated stress distributionsnear the device.

FIG. 6. Pictures of various points of integration of mm-NFC devices onthe body, each suggestive of a different application possibility. (a)Picture of a device on the fingernail. Pictures of applications tounlock a (b) smartphone and (c) computer (using a mouse). (d) Picture ofa set of devices with integrated LEDs mounted on the fingernails. (e, f)Pictures of a device mounted on the skin behind the ear, with integratedtemperature sensing capabilities. (inset) Picture of a device thatenables temperature sensing. Pictures of devices (g) on a tooth and (h)submerged in water.

FIG. 7. The effective inductance of the coil of mm-NFC devices withdifferent bending radii of curvature to determine the shift of resonancefrequency.

FIG. 8. (a) The return loss spectra for three mm-NFC devices. (b) Thechange of the phases of primary coil to analyze the size effect of themm-NFC device on the communication between the primary coil and mm-NFCdevice.

FIG. 9. The illustration of the primary coil and the mm-NFC device formeasurement. The mm-NFC device is located at the center of the primarycoil at the vertical distance of ˜2 mm.

FIG. 10 provides images and experimental results characterizing afingernail mounted silicon CMOS device. Bonding to the surface offingernail is provided by cyanoacrylate providing excellent adhesion.The plots provided demonstrate good electronic performance achieved fora timeframe of about 2.5 months.

FIG. 11 provides images of fingernail authentication device designs. Thepanel to the left shows a fingernail mounted system comprising NFC coilsand NFC chip components provided in a miniaturized format. The panel tothe right shows a fingernail mounted system further comprising an energyharvesting LED indicator also provided in a miniaturized format.

FIG. 12 provides a summary of design information characterizing thecalculated Q factor for NFC fingernail mounted systems. As shown in thisfigure the Q factor is dependent on a number of variables including thethickness and diameter of the NFC coils. High Q factor is beneficial forcommunication with a mobile electronic device, such as a cell phone.

FIG. 13 provides a plot of S21 (dB0) as a function of frequency for aseries of NFC fingernail mounted system designs. The S21 represents thepower transferred between the primary NFC coil from a Samsung cell phoneand the secondary NFC coil from the fingernail mounted NFC system. Thedistance between the primary and secondary coils is set at 5 mm.

FIG. 14 shows a fingernail mounted NFC system for use in conjunctionwith a mouse for authentication of a user to a computer.

FIG. 15 provides a summary of electromagnetic properties as a functionof the radius of curvature. These results demonstrate that thefingernail mounted NFC systems operate at similar ranges regardless offingernail curvature.

FIG. 16 provides an image of a 6″ by 9″ test panel comprising 252 NFCsystems of the invention for tissue mounting applications.

FIG. 17, A-F provides schematic diagrams of various tissue mountedsystems of the invention.

FIG. 18 provides a schematic illustration of a tissue mounted NFC devicemounted on the fingernail for authentication in connection with use of afirearm.

FIG. 19 provides a process flow diagram illustrating a method for makingdevices of the invention.

FIG. 20 provides an illustration of the interface of a device of thepresent invention with a mobile device, such as a mobile phone.

FIG. 21 provides a description of example applications of the presentdevices in hospital and clinical settings.

FIG. 22 provides photographs and a device schematic (inset) ofultraminiaturized, UV sensors of the invention.

FIG. 23 provides a schematic illustration of example applications ofdevices of the invention for skin or nail mounted sensors of exposure inUV phototherapy.

FIG. 24 provides a schematic illustration of example applications ofdevices of the invention for phototherapy in the NICU.

FIG. 25 provides a schematic illustration of example applications ofdevices of the invention for infectious disease compliance.

FIG. 26 provides a schematic illustration of example applications ofdevices of the invention for infectious disease compliance.

FIG. 27 provides a schematic illustration of example applications ofdevices of the invention for infectious disease compliance.

FIG. 28 provides a schematic illustration of example applications ofdevices of the invention for pulse oximetry and colorimeter.

FIG. 29 provides a schematic illustration of example applications ofdevices of the invention for pulse rate monitoring.

FIG. 30 provides a schematic illustration of example applications ofdevices of the invention for oximetry.

FIG. 31 provides a schematic illustration a device of the invention forfingernail oximetry.

FIG. 32 provides a schematic illustration a device of the inventionemploying deployment via a pull tab configuration.

FIG. 33 provides a schematic illustration of example applications ofdevices of the invention for authentication.

FIG. 34 provides a schematic illustration of example applications ofdevices of the invention

DETAILED DESCRIPTION OF THE INVENTION

In general, the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. The followingdefinitions are provided to clarify their specific use in the context ofthe invention.

The terms “flexible” and “bendable” are used synonymously in the presentdescription and refer to the ability of a material, structure, device ordevice component to be deformed into a curved or bent shape withoutundergoing a transformation that introduces significant strain, such asstrain characterizing the failure point of a material, structure, deviceor device component. In an exemplary embodiment, a flexible material,structure, device or device component may be deformed into a curvedshape without introducing strain larger than or equal to 5%, for someapplications larger than or equal to 1%, and for yet other applicationslarger than or equal to 0.5% in strain-sensitive regions. A used herein,some, but not necessarily all, flexible structures are also stretchable.A variety of properties provide flexible structures (e.g., devicecomponents) of the invention, including materials properties such as alow modulus, bending stiffness and flexural rigidity; physicaldimensions such as small average thickness (e.g., less than 100 microns,optionally less than 10 microns and optionally less than 1 micron) anddevice geometries such as thin film and mesh geometries.

The term “tissue” is used broadly to describe any types of material ofwhich animals or plants are made, for example, consisting of specializedcells and their products. A used herein tissue may refer to cellscorresponding to one or more organs, such as cells that substantiallycarry out the same or complementary functions. Tissue as referred toherein may correspond to animals, including human and non-human animals(e.g., livestock, veterinary animals, etc.), and plants. Tissue asreferred to herein may correspond to living cells or dead cells whichmay include, but are not limited to, the corpus unguis, (e.g.,fingernail, toenail, claw hoof, horn, etc.). Examples of tissues includeskin, a fingernail, a toenail, a tooth, a bone, hair or an ear lobe.

“Stretchable” refers to the ability of a material, structure, device ordevice component to be strained without undergoing fracture. In anexemplary embodiment, a stretchable material, structure, device ordevice component may undergo strain larger than 0.5% without fracturing,for some applications strain larger than 1% without fracturing and foryet other applications strain larger than 3% without fracturing. As usedherein, many stretchable structures are also flexible. Some stretchablestructures (e.g., device components) are engineered to be able toundergo compression, elongation and/or twisting so as to be able todeform without fracturing. Stretchable structures include thin filmstructures comprising stretchable materials, such as elastomers; bentstructures capable of elongation, compression and/or twisting motion;and structures having an island—bridge geometry. Stretchable devicecomponents include structures having stretchable interconnects, such asstretchable electrical interconnects.

“Functional layer” refers to a device-containing layer that imparts somefunctionality to the device. For example, the functional layer may be athin film such as a semiconductor layer. Alternatively, the functionallayer may comprise multiple layers, such as multiple semiconductorlayers separated by support layers. The functional layer may comprise aplurality of patterned elements, such as interconnects running betweendevice-receiving pads or islands. The functional layer may beheterogeneous or may have one or more properties that are inhomogeneous.“Inhomogeneous property” refers to a physical parameter that canspatially vary, thereby effecting the position of the neutral mechanicalsurface (NMS) within the multilayer device.

“Semiconductor” refers to any material that is an insulator at a lowtemperature, but which has an appreciable electrical conductivity attemperatures of approximately 300 Kelvin. In the present description,use of the term semiconductor is intended to be consistent with use ofthis term in the art of microelectronics and electronic devices. Usefulsemiconductors include those comprising element semiconductors, such assilicon, germanium and diamond, and compound semiconductors, such asgroup IV compound semiconductors such as SiC and SiGe, group III-Vsemiconductors such as AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP,InSb, InAs, InN, and InP, group III-V ternary semiconductors alloys,such as Al_(x)Ga_(1-x)As, group II-VI semiconductors, such as CsSe, CdS,CdTe, ZnO, ZnSe, ZnS, and ZnTe, group I-VII semiconductors, such asCuCl, group IV-VI semiconductors, such as PbS, PbTe and SnS, layersemiconductors, such as Pbl₂, MoS₂ and GaSe, and oxide semiconductors,such as CuO and Cu₂O. The term semiconductor includes intrinsicsemiconductors and extrinsic semiconductors that are doped with one ormore selected materials, including semiconductors having p-type dopingmaterials and n-type doping materials, to provide beneficial electronicproperties useful for a given application or device. The termsemiconductor includes composite materials comprising a mixture ofsemiconductors and/or dopants. Specific semiconductor materials usefulfor some embodiments include, but are not limited to, Si, Ge, SiC, AlP,AlAs, AlSb, GaN, GaP, GaAs, GaSb, InP, InAs, GaSb, InP, InAs, InSb, ZnO,ZnSe, ZnTe, CdS, CdSe, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, PbS, PbSe,PbTe, AlGaAs, AlInAs, AlInP, GaAsP, GaInAs, GaInP, AlGaAsSb, AlGaInP,and GaInAsP. Porous silicon semiconductor materials are useful forapplications of aspects described herein in the field of sensors andlight emitting materials, such as light emitting diodes (LEDs) and solidstate lasers. Impurities of semiconductor materials are atoms, elements,ions and/or molecules other than the semiconductor material(s)themselves or any dopants provided to the semiconductor material.Impurities are undesirable materials present in semiconductor materials,which may negatively impact the electronic properties of semiconductormaterials, and include but are not limited to oxygen, carbon, and metalsincluding heavy metals. Heavy metal impurities include, but are notlimited to, the group of elements between copper and lead on theperiodic table, calcium, sodium, and all ions, compounds and/orcomplexes thereof.

“Coincident” refers to the relative position of two or more objects,planes or surfaces, for example a surface such as a neutral mechanicalsurface (NMS) or neutral mechanical plane (NMP) that is positionedwithin or is adjacent to a layer, such as a functional layer, substratelayer, or other layer. In an embodiment, a NMS or NMP is positioned tocorrespond to the most strain-sensitive layer or material within thelayer. “Proximate” refers to the relative position of two or moreobjects, planes or surfaces, for example a NMS or NMP that closelyfollows the position of a layer, such as a functional layer, substratelayer, or other layer while still providing desired flexibility orstretchability without an adverse impact on the strain-sensitivematerial physical properties. In general, a layer having a high strainsensitivity, and consequently being prone to being the first layer tofracture, is located in the functional layer, such as a functional layercontaining a relatively brittle semiconductor or other strain-sensitivedevice element. A NMS or NMP that is proximate to a layer need not beconstrained within that layer, but may be positioned proximate orsufficiently near to provide a functional benefit of reducing the strainon the strain-sensitive device element when the device is folded.

In this aspect, “strain-sensitive” refers to a material that fracturesor is otherwise impaired in response to a relatively low level ofstrain. In an aspect, the NMS is coincident or proximate to a functionallayer. In an aspect the NMS is coincident to a functional layer,referring to at least a portion of the NMS located within the functionallayer that contains a strain-sensitive material for all laterallocations along the NMS. In an aspect, the NMS is proximate to afunctional layer, wherein although the NMS may not be coincident withthe functional layer, the position of the NMS provides a mechanicalbenefit to the functional layer, such as substantially lowering thestrain that would otherwise be exerted on the functional layer but forthe position of the NMS. For example, the position of a proximate NMS isoptionally defined as the distance from the strain-sensitive materialthat provides an at least 10%, 20%, 50% or 75% reduction in strain inthe strain-sensitive material for a given folded configuration, such asa device being folded so that the radius of curvature is on the order ofthe millimeter or centimeter scale. In another aspect, the position of aproximate NMS can be defined in absolute terms such as a distance fromthe strain-sensitive material, such as less than several mm, less than 2mm, less than 10 μm, less than 1 μm, or less than 100 nm. In anotheraspect, the position of a proximate layer is defined relative to thelayer that is adjacent to the strain-sensitive material, such as within50%, 25% or 10% of the layer closest to the strain-sensitive-containinglayer. In an aspect, the proximate NMS is contained within a layer thatis adjacent to the functional layer.

A “component” is used broadly to refer to an individual part of adevice.

“Sensing” refers to detecting the presence, absence, amount, magnitudeor intensity of a physical and/or chemical property. Useful devicecomponents for sensing include, but are not limited to electrodeelements, chemical or biological sensor elements, pH sensors,temperature sensors, strain sensors, mechanical sensors, positionsensors, optical sensors and capacitive sensors.

“Actuating” refers to stimulating, controlling, or otherwise affecting astructure, material or device component. Useful device components foractuating include, but are not limited to, electrode elements,electromagnetic radiation emitting elements, light emitting diodes,lasers, magnetic elements, acoustic elements, piezoelectric elements,chemical elements, biological elements, and heating elements.

The terms “directly and indirectly” describe the actions or physicalpositions of one component relative to another component. For example, acomponent that “directly” acts upon or touches another component does sowithout intervention from an intermediary. Contrarily, a component that“indirectly” acts upon or touches another component does so through anintermediary (e.g., a third component).

“Encapsulate” refers to the orientation of one structure such that it isat least partially, and in some cases completely, surrounded by one ormore other structures, such as a substrate, adhesive layer orencapsulating layer. “Partially encapsulated” refers to the orientationof one structure such that it is partially surrounded by one or moreother structures, for example, wherein 30%, or optionally 50%, oroptionally 90% of the external surface of the structure is surrounded byone or more structures. “Completely encapsulated” refers to theorientation of one structure such that it is completely surrounded byone or more other structures.

“Dielectric” refers to a non-conducting or insulating material.

“Polymer” refers to a macromolecule composed of repeating structuralunits connected by covalent chemical bonds or the polymerization productof one or more monomers, often characterized by a high molecular weight.The term polymer includes homopolymers, or polymers consistingessentially of a single repeating monomer subunit. The term polymer alsoincludes copolymers, or polymers consisting essentially of two or moremonomer subunits, such as random, block, alternating, segmented,grafted, tapered and other copolymers. Useful polymers include organicpolymers or inorganic polymers that may be in amorphous, semi-amorphous,crystalline or partially crystalline states. Crosslinked polymers havinglinked monomer chains are particularly useful for some applications.Polymers useable in the methods, devices and components include, but arenot limited to, plastics, elastomers, thermoplastic elastomers,elastoplastics, thermoplastics and acrylates. Exemplary polymersinclude, but are not limited to, acetal polymers, biodegradablepolymers, cellulosic polymers, fluoropolymers, nylons, polyacrylonitrilepolymers, polyamide-imide polymers, polyimides, polyarylates,polybenzimidazole, polybutylene, polycarbonate, polyesters,polyetherimide, polyethylene, polyethylene copolymers and modifiedpolyethylenes, polyketones, poly(methyl methacrylate),polymethylpentene, polyphenylene oxides and polyphenylene sulfides,polyphthalamide, polypropylene, polyurethanes, styrenic resins,sulfone-based resins, vinyl-based resins, rubber (including naturalrubber, styrene-butadiene, polybutadiene, neoprene, ethylene-propylene,butyl, nitrile, silicones), acrylic, nylon, polycarbonate, polyester,polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyolefinor any combinations of these.

“Elastomer” refers to a polymeric material which can be stretched ordeformed and returned to its original shape without substantialpermanent deformation. Elastomers commonly undergo substantially elasticdeformations. Useful elastomers include those comprising polymers,copolymers, composite materials or mixtures of polymers and copolymers.Elastomeric layer refers to a layer comprising at least one elastomer.Elastomeric layers may also include dopants and other non-elastomericmaterials. Useful elastomers include, but are not limited to,thermoplastic elastomers, styrenic materials, olefinic materials,polyolefin, polyurethane thermoplastic elastomers, polyamides, syntheticrubbers, PDMS, polybutadiene, polyisobutylene,poly(styrene-butadiene-styrene), polyurethanes, polychloroprene andsilicones. Exemplary elastomers include, but are not limited to siliconcontaining polymers such as polysiloxanes including poly(dimethylsiloxane) (i.e. PDMS and h-PDMS), poly(methyl siloxane), partiallyalkylated poly(methyl siloxane), poly(alkyl methyl siloxane) andpoly(phenyl methyl siloxane), silicon modified elastomers, thermoplasticelastomers, styrenic materials, olefinic materials, polyolefin,polyurethane thermoplastic elastomers, polyamides, synthetic rubbers,polyisobutylene, poly(styrene-butadiene-styrene), polyurethanes,polychloroprene and silicones. In an embodiment, a polymer is anelastomer.

“Conformable” refers to a device, material or substrate which has abending stiffness that is sufficiently low to allow the device, materialor substrate to adopt a contour profile desired for a specificapplication, for example a contour profile allowing for conformalcontact with a surface having a non-planar geometry such as a surfacewith relief features or a dynamic surface (e.g. changes with respect totime). In certain embodiments, a desired contour profile is that of afinger nail, skin, tooth, toe nail or ear lobe.

“Conformal contact” refers to contact established between a device and areceiving surface. In one aspect, conformal contact involves amacroscopic adaptation of one or more surfaces (e.g., contact surfaces)of a device to the overall shape of a surface. In another aspect,conformal contact involves a microscopic adaptation of one or moresurfaces (e.g., contact surfaces) of a device to a surface resulting inan intimate contact substantially free of voids. In an embodiment,conformal contact involves adaptation of a contact surface(s) of thedevice to a receiving surface(s) such that intimate contact is achieved,for example, wherein less than 20% of the surface area of a contactsurface of the device does not physically contact the receiving surface,or optionally less than 10% of a contact surface of the device does notphysically contact the receiving surface, or optionally less than 5% ofa contact surface of the device does not physically contact thereceiving surface.

“Young's modulus” or “modulus” are used interchangeably and refer to amechanical property of a material, device or layer which refers to theratio of stress to strain for a given substance. Young's modulus may beprovided by the expression:

$\begin{matrix}{{E = {\frac{({stress})}{({strain})} = {\left( \frac{L_{0}}{\Delta\; L} \right)\left( \frac{F}{A} \right)}}},} & (I)\end{matrix}$where E is Young's modulus, L₀ is the equilibrium length, ΔL is thelength change under the applied stress, F is the force applied, and A isthe area over which the force is applied. Young's modulus may also beexpressed in terms of Lame constants via the equation:

$\begin{matrix}{{E = \frac{\mu\left( {{3\lambda} + {2\mu}} \right)}{\lambda + \mu}},} & ({II})\end{matrix}$where λ and μ are Lame constants. High Young's modulus (or “highmodulus”) and low Young's modulus (or “low modulus”) are relativedescriptors of the magnitude of Young's modulus in a given material,layer or device. In some embodiments, a high Young's modulus is largerthan a low Young's modulus, preferably about 10 times larger for someapplications, more preferably about 100 times larger for otherapplications, and even more preferably about 1000 times larger for yetother applications. In an embodiment, a low modulus layer has a Young'smodulus less than 100 MPa, optionally less than 10 MPa, and optionally aYoung's modulus selected from the range of 0.1 MPa to 50 MPa. In anembodiment, a high modulus layer has a Young's modulus greater than 100MPa, optionally greater than 10 GPa, and optionally a Young's modulusselected from the range of 1 GPa to 100 GPa. In an embodiment, a deviceof the invention has one or more components having a low Young'smodulus. In an embodiment, a device of the invention has an overall lowYoung's modulus.

“Low modulus” refers to materials having a Young's modulus less than orequal to 10 MPa, less than or equal to 20 MPa or less than or equal to 1MPa.

“Bending stiffness” is a mechanical property of a material, device orlayer describing the resistance of the material, device or layer to anapplied bending movement. Generally, bending stiffness is defined as theproduct of the modulus and area moment of inertia of the material,device or layer. A material having an inhomogeneous bending stiffnessmay optionally be described in terms of a “bulk” or “average” bendingstiffness for the entire layer of material.

“Lateral dimensions” refer to physical dimensions of a structure such asa tissue mounted electronic system or component thereof. For example,lateral dimensions may refer to one or more physical dimensions orientedorthogonal to axes extending along the thickness of a structure, such asthe length, the width, the radius or the diameter of the structure.Lateral dimensions are useful for characterizing the area of anelectronic system or component thereof, such as characterizing thelateral area footprint of a system corresponding to a two dimensionalarea in a plane or a surface positioned orthogonal to axes extendingalong the thickness of the structure.

FIG. 1A provides a top plan view and FIG. 1B provides a side explodedview of a tissue mounted system comprising a fingernail mounted NFCdevice. The device of this embodiment supports wearable electronicapplications compatible with communication with cellular phones, andother NFC enabled communication platforms. A broad range of near fieldcommunication applications is supported by the present systems includingpassword authentication, electronic transactions, biosensing, and motionrecognition.

As shown in FIGS. 1A and 1B, the fingernail mounted NFC device comprisesa multilayer structure including electronically and/or opticallyfunctional layers and structural and/or electrically insulated layers.The device of this embodiment has miniaturized overall dimensions on themillimeter scale. As shown in FIG. 1B the functional layers comprise apair of copper NFC indication coils and LED and NFC chip components. Thecoils are a characterized by radii greater than approximately 5 mm andthicknesses of approximately 20 microns. The LED and NFC chip componentsare characterized by thicknesses of approximately 100 microns. As shownin FIG. 1, the NFC chip component electrically connects to the coils viacontacts located near center regions of the coils.

As shown in FIG. 1B, the NFC device further includes structural and/orelectrically insulated layers comprising polyimide coatings that arepositioned to physically encapsulate the copper coils and an adhesive,such as a low modulus acrylic, serving as the substrate. In someembodiments, for example, a thin silicone elastomer (e.g., less than 100microns) is provided to encapsulate the system. In some embodiments,structural and/or electrically insulated layers (e.g. polyimidecoatings, adhesive, etc.) have thicknesses and positions placingfunctional device elements, e.g., the coils or chips, coincident with orproximate to the neutral mechanical surface of the device.

In the example shown in FIGS. 1A and 1B, mounting on the externalsurface of fingernail is provided. In these embodiments, the system mayhave overall physical properties providing overall flexibilitysufficient to achieve mechanically robust and conformal contact with thecurvilinear surface of the fingernail. Systems of the invention are alsocompatible with mounting on a variety of tissue surfaces includingexternal tissues such as the tooth, toenail, ear lobe, hair and skin.Mounting on the fingernail, however, provides certain benefits usefulfor some applications including very stable and mechanically robustmounting for time periods greater than 6 months with a low risk fordiscomfort or delamination. The example systems shown in FIGS. 1A and 1Balso provide a platform compatible with multifunctional implementationwherein additional electronic and/or photonic systems are integratedinto the system. The example systems shown in FIGS. 1A and 1B are alsocompatible with overall device designs for preventing removal and/orre-use, for example, by providing for loss of functionality and/ordestruction upon attempted removal.

Example 1

Abstract

This Example introduces a class of thin, lightweight, flexible nearfield communication (NFC) devices with ultraminiaturized format, andpresents systematic investigations of the mechanics, radio frequencycharacteristics and materials aspects associated with their optimizedconstruction. These systems allow advantages in mechanical strength,placement versatility, and minimized interfacial stresses compared toother NFC technologies and wearable electronics. Detailed experimentalstudies and theoretical modeling of the mechanical and electromagneticproperties of these systems establish understanding of the key designconsiderations. These concepts can apply to many other types of wirelesscommunication systems including bio-sensors and electronic implants.

Introduction

Wearable electronic technologies form the foundation for a rapidlygrowing consumer device segment. Projections suggest that over $100billion will be spent in materials alone over the coming decade in thepursuit of new wearable devices^([1]). Advances in materials and devicearchitectures for these systems will create opportunities for increasingthe range of capabilities, expanding the modes of use, improving therobustness/reliability, reducing the size/weight and lowering the cost.The cellular phone platform will likely remain a key element in thebroader technology landscape, as in currently available wrist band andwatch style devices that measure body processes and communicate data tothe phone^([2,3]). Recent research demonstrates much different types ofintegration strategies compared to those of these existing systems, inwhich the wearable devices take the form of temporary transfer tattoos.The result is greatly improved contact with the body and correspondingincreases in the diversity and accuracy of information that can becollected from integrated sensors^([2,4,5]). Here, an overarching goalis to engineer the physical properties, and in particular the elasticmodulus and elastic stretchability, to match those of the epidermis, asa way to reduce irritation and discomfort at the skin interface and toimprove the robustness of the bonding^([2,4,6]). In this Example, wepresent a complementary strategy, in which overall size miniaturizationserves as an additional, and sometimes primary, means for minimizingphysical effects on the skin. This scheme also expands the options inmounting locations, to include areas such as the fingernails and theteeth, where mechanical compliance is not always required and wheremounting times can extend to several months, or more. In particular, weintroduce thin, lightweight, flexible near field communication (NFC)devices in ultraminiaturized formats, along with systematic studies ofthe mechanics and materials aspects associated with their optimizedconstruction. The potential applications include passwordauthentication^([7]), electronic transactions^([8]) and biometricsensing^([9]), each performed via wireless power and communication tocellular phones or other NFC enabled platforms. Such devices consumenearly one hundred times less area than conventional wrist-worn NFCdevices and they are ˜100 and ˜10,000 times thinner and lighter inweight, respectively. The areas are also nearly ten times smaller thanthose of recently reported NFC devices with epidermal construction^([2])and are, to our knowledge, the smallest to be explored for integrationon the surface of the human body. Rigid, capsule-shaped NFC devices withvolumes ˜10 times larger than those of the devices reported here areavailable for implantation into the human body^([10]). Open architecturedesigns provide a high tolerance to deformation and physical stresseswhen mounted on soft surfaces such as the epidermis. Experimentalmeasurements of the mechanical and electromagnetic properties comparefavorably to theoretical modeling results. Device operation usingstandard NFC enabled consumer electronics demonstrate the capabilitiesin evaluations that are supportive of a range of applications.

Results and Discussion

FIG. 2 summarizes the layered, open architecture designs of theseultraminiaturized, or millimeter-scale, NFC (mm-NFC) devices. FIG. 2a, bshows optical microscope images of mm-NFC devices with diameters of 5.8mm and 7.04 mm. For both cases, each of the coils in the dual-coillayout consist of copper traces with 9 turns (18 μm thick), to enablehigh Q factors and resonance frequencies near 14 MHz. These platformsexploit thinned NFC die selected from a range of commercially availablecomponents. The experiments reported here use NTAG216 (NXPsemiconductor) and M24LR04E (ST Microelectronics) chips with the 5.8 mmand 7.04 mm diameter coils, respectively. The devices incorporatepolyimide coatings above and below each layer to physically encapsulatethe copper traces and place them near the neutral mechanical plane tominimize bending induced strains (FIG. 2d, e ). The NFC dies connect viaa modified flip-chip technique to contacts located near the centerregions of the coils. Certain device variants also include small-scalelight emitting diodes (LEDs, 0402 size: 1 mm×0.5 mm). Here, energyharvested and rectified during communication within NFC ISO protocolsenables operation of the LEDs and the NFC chips simultaneously. In allcases, a thin silicone elastomer (˜25 μm) encapsulates the system, and alow modulus acrylic adhesive (˜25 μm) serves as the substrate. Theultraminiaturized, thin, lightweight construction provides wide rangingoptions for mounting on the human body, including locations wherelong-term integration is possible and where interfaces to both the bodyand an external device are easily established.

The fingernails and toenails provide examples. By comparison to theskin, the nails are hard, physically static and they lack sensorycapacity, thereby providing a minimally invasive interface for robust,long-term integration. The growth cycle from the quick to the end of thenail can exceed 6 months, thereby allowing integration for severalmonths^([11]). Such timeframes greatly exceed those associated withmounting on the skin, where the cycle for skin cell differentiation andexfoliation occurs on the timescale of a few weeks. The fingernails ofadults have radii of curvature that range from ˜13 mm to ˜5 mm,depending on age, sex, overall body size, and finger^([12]). Properlydesigned devices can accommodate bending associated with mounting onsuch surfaces, without significant change in operating characteristics.FIG. 3 shows the electromagnetic properties of mm-NFC devices at bendingcurvatures relevant to the fingernail. These evaluations use the largestdevice (7.04 mm coil diameter) because this format involves the mostsignificant change at any given curvature. In all cases, resonancefrequencies measured by the Min-phase method^([13]) match thosedetermined by electromagnetic simulations (Ansys HFSS 13 User's guide,Ansys Inc. 2011). Typically, the frequencies increase with bending radiidue to decreases in the projected areas and the associated inductances.The magnetic flux through the coil of the mm-NFC device is Φ=∫∫_(S)B·dS, where B is magnetic field produced by the primary coil and S isthe corresponding in-plane area enclosed by the coil of the mm-NFCdevice. For a large commercial primary coil (Samsung Galaxy Note II),the magnetic field B remains essentially the same when the small mm-NFCdevices are bent, such that the magnetic flux ϕ depends only on theeffective area S of the coil of the mm-NFC device. The change ofeffective area S is (d/R)²/32, where d is the inner diameter of themm-NFC device and R is the radius of curvature. For the mm-NFC devicewith 7.04 mm outer diameter d=˜5 mm as in experiments and R>5 mm for theadult human fingernails, the effective area S only decreases by ˜3.1%for R=5 mm. The magnetic flux therefore also remains unchanged when themm-NFC devices are mounted onto the fingernails, as confirmed by FIG. 3a. The resonance frequency can be obtained from fresonant=1/(2π√{squareroot over (L(fresonant,R)C)}), where C is the capacitance of the NFCdie, and the effective inductance L of the coil of the mm-NFC devicedepends on the frequency f and radius of curvature R as shown in FIG. 7.The maximum difference between the effective inductance for a planarcoil and one with a radius of curvature of 5 mm is only ˜3% as shown inFIG. 7. By consequence, the resonance frequencies and the Q factorsremain ˜14 MHz and ˜15, respectively, for a bending radius R>˜5 mm.Changes can be observed when R becomes significantly smaller than 5 mm,as shown in FIG. 3 d, e.

The electromagnetic coupling between a primary coil and an mm-NFC devicedepends strongly on size, as expected from the expression for magneticflux. Three mm-NFC devices with different radii given in Table 1 arestudied, where the number of turns and layers are adjusted to offer thesame inductances, i.e., these mm-NFC devices have the same resonantfrequency and Q factor as shown in Table 1 and return loss spectra asshown in FIG. 8a . As the size of mm-NFC device decreases, the amplitudeof phase decreases rapidly as shown in FIG. 8b , which suggests that thecommunication between the primary coil and mm-NFC device weakenssignificantly as the coil size of an mm-NFC device decreases.

TABLE 1 Three mm-NFC devices with different radii Diameter Lay- Turns/Resonant Inductance Q factor (mm) ers layer frequency f₀ at f₀ (μH) atf₀ Coil 1 7.76 2 8 13.88 MHz 4.76 13.9 Coil 2 7.04 2 9 13.72 MHz 4.8713.4 Coil 3 4 4 8 13.93 MHz 4.73 12.3

The nature of fingernail growth affords increased mounting times formm-NFC devices that adopt elliptical shapes with major axes orientedparallel to the base of the nail. FIG. 4 shows the results for mm-NFCdevices with such shapes and with areas similar to those of circulardesigns (πR²), for several different aspect ratios b/a=1.21, 1.44, and1.69, with the major axes a and b shown in FIG. 4c . The resonancefrequency and the amplitude of the phase decrease only slightly as theaspect ratio b/a increases as shown in FIG. 4b, c . As a result, theresonance frequencies and the Q factors remain essentially unchanged,i.e. 14 MHz and 15, respectively, for this range of aspect ratios (FIG.4d, e ).

Flexible mm-NFC devices also offer advantages for mounting on the skin.Here, the small sizes minimize sensory perception and reduce energyrelease rates for delamination. FIG. 5a shows images of a device with7.04 mm outer diameter printed onto a low modulus substrate (PDMS, 20 mmlength in stretching direction, 25 mm width, 3 mm thick, 0.145 MPamodulus) in various deformed states, including tests that involvestretching to 20% and compressing to 20%, repeatedly. Even after 10,000cycles, the device shows no form of degradation in properties (FIG. 5c). FIG. 5b presents the stress distributions at the interface betweenthe substrate and mm-NFC device obtained from finite element analysis(ABAQUS Analysis User's Manual 2010, V6.10). For both stretching andcompressing, the normal stress is negligibly small as compared to theshear stress at the interface; the latter is smaller than the threshold(20 kPa)^([14]) for somatosensory perception of forces by normal skinunder 20% stretching. For compressing by 20%, which is larger than thatexpected in most practical applications, the shear stress exceeds thethreshold 20 kPa over a small region (˜4 mm²) of the interface. Theenergy release rate^([15]) for an infinitesimal crack at the edge is

${G = {\frac{E_{sub}ɛ_{app}^{2}}{8\left( {1 - v_{sub}^{2}} \right)}L_{0}\tan\frac{\pi\; D}{2L_{0}}}},$where D is the diameter of the mm-NFC device, L₀ is the length ofsubstrate in the stretching direction, ε_(app) is the average strain inthe substrate, and E_(sub) and v_(sub) are the Young's modulus andPoisson's ratio of the substrate, respectively. As shown in FIG. 5d ,the energy release rate clearly decreases with the coil diameter D, andbecomes linear with respect to D for small mm-NFC devices,

${i.e.\mspace{11mu} G} = {\frac{\pi\;{DE}_{sub}ɛ_{app}^{2}}{16\left( {1 - v_{sub}^{2}} \right)}.}$This scaling affords advantages in the reduced possibility fordelamination of mm-NFC devices from the skin. FIG. 5e, f show thepicture of a device mounted on the skin during a pinching modedeformation and the stress distributions at the interface from finiteelement analysis, respectively. The device is fully bonded with the skineven when the skin is subjected to severe wrinkle. Minimizing the sizemaximizes the robustness of the device/skin bonding interface for anygiven adhesive strategy and device construction.

FIG. 6 presents images of devices mounted on various locations of thebody, each suggestive of a possible application. FIG. 6a shows an mm-NFCdevice on the fingernail, such that, for example, natural motionsassociated with handling the phone could unlock its operation, as shownin FIG. 6b . This type of authentication could be useful in manycontexts (FIG. 6c ). Multiple devices with different purposes can easilybe accommodated in one convenient area (FIG. 6d ). Certain NFC die(SL13A, AMS AG) offer integrated capabilities in temperature sensing andother functionality. The inset of FIG. 6e shows an mm-NFC device fortemperature sensing. In this case, a skin-integrated configuration couldbe useful (FIG. 6e, f ). The devices can also function properly on teethand under water (FIG. 6g, h ), thereby supporting modes for chemicalsensing in biofluids.

Conclusion

The materials, device designs and integration strategies presented hereprovide a framework for mm-scale, flexible, body-worn NFC systems, withpotential applications in password authentication, electronictransactions and biometric sensing. The ultraminiaturized geometries andmechanically flexible designs, in particular, afford advantages inmechanical strength, placement versatility, and minimized interfacialstresses. Combined theoretical and experimental considerations inmaterials, electromagnetic characteristics and mechanical properties areessential to proper design. These concepts can apply to many other typesof wireless communication systems including various bio-sensors andelectronic implants.

Experimental Section

Fabrication of the Coils:

A Cu foil (18 μm thick, Oak Mitsui Micro-thin series) served as thematerial for the first coil layer. A layer of polyimide (2.4 μm thick,PI2545, HD Microsystems) spin-cast at 2000 rpm for 30 s, baked on a hotplated at 150° C. for 5 min, and in a vacuum oven at 250° C. for 70 minformed an insulating coating. Laminating this PI-coated Cu foil onto aglass slide coated with polydimethylsiloxane (PDMS, Sylgard 184), withthe PI side down, allowed patterning of the Cu into a coil geometry byphotolithography (AZ 4620 photo-resist, spin-casting at 3000 rpm for 30s, baking at 110° C. for 3 mins, UV irradiance for 300 mJ/cm²,development for ˜40 s with developer AZ 400K/deionized water solution of1:2 volume ratio) and wet etching (CE-100 copper etchant, Transense,etching for ˜10 mins with frequent rinsing by water). A coating of PIspin-cast at 1000 rpm for 30 s covered the first coil layer.Photolithography (AZ 4620) and oxygen plasma etching created via holesthrough the PI. Oxide remover (Flux, Worthington) eliminated the nativecopper oxide at the base of via holes. Electron beam evaporation formeda conducting layer (500 nm thick) for electroplating. Next,electroplating (11 wt % cupric sulfate pentahydrate in water, current of13 mA/cm² for 55 mins, distance between positive electrode and negativeelectrode of 1.7 cm) generated a second coil in a 20 μm thick layer ofCu, also patterned by photolithography (AZ 4620) and wet etching (copperetchant). Spin casting formed another 2.4 μm thick layer of PI over theentire coil structure. Electron beam evaporation of a 50 nm thick layerof SiO₂ created a hard mask in a geometry defined by photolithography(AZ 4620) and RIE etching (50 mTorr, 40 sccm CF₄, 100 W for 10 min).Oxygen plasma removed the exposed PI, leaving PI only in the regions ofthe coil, for an open architecture design that improves the mechanicaldeformability.

NFC Die:

The NTAG216 (NXP Semiconductor, ISO/IEC 14443, input capacitance of 50pF) chip served as the electronics for the smallest device. The M24LR04E(ST Microelectronics, ISO/IEC 15693, input capacitance of 27.5 pF) chipwas used for the energy harvesting device. The SL13A (AMS AG, ISO/IEC15693, input capacitance of 25 pF) chip enabled the temperature sensingdevice. All chips were thinned (<100 μm thick) and used as bare diewithout packages.

Transfer and Chips Assembly:

A cellulose-based water-soluble tape (Grainger) allowed retrieval of thefabricated coils from the substrate and integration onto an adhesivesubstrate. Removal of the water-soluble tape by dissolution in watercompleted the transfer. Thinned NFC die and LEDs attached to the coil bya modified flip-chip bonding method with an Indium/Ag based solder paste(Ind. 290, Indium Corporation; ˜165° C. for 2 min in a reflow oven). Adroplet of silicone elastomer (Q1-4010, Dow corning) encapsulated thechips.

Electromagnetic Characterization:

Electromagnetic characterization used an impedance analyzer (4291A RFimpedance/material analyzer, Hewlett Packard) with a commercial primarycoil (Samsung Galaxy Note II; resonant frequency ˜47.5 MHz) over afrequency range of 5 to 20 MHz. The Min-phase method defined theresonance frequencies of the NFC devices. Measurements involvedplacement of the device at the center of the primary coil at a verticaldistance of ˜2 mm, as shown FIG. 9.

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Example 2—Fingernail Mounted NFC Device for Password Authentication

The invention provides, for example, a fingernail mounted near fieldcommunication (NFC) device providing a unique solution for passwordauthentication in the electronic hardware industry. The materials,design, and circuit integration enable the art of biocompatible NFCtechnology. The built-in NFC technology serves as a digital replacementfor passwords, pin numbers, security questions, distinct biometrics,and/or text/email verification dealings. The fingernail-mounted deviceof this embodiment is able to wirelessly communicate with point ofaccess readers that use NFC antennas. The point of access readersinclude but are not limited to smartphones, laptops, keyboards, computermice, remote controls, safes, and/or locks. Instead of recallingpasswords, fingerprint touch pads, or safe combinations, authorizedfingernail-mounted device users are granted instant access to theirelectronics and/or safe belongings without producing security passcodes.

In some embodiments, for example, the invention has a devoted chip thatstores an encrypted identification number that is unique to eachindividual device. In addition, the chip has action-specific securitycodes that change after each point of authorization. The encryptedidentification numbers grant access to authorized users. For instance,the authorized user goes straight to his or her home screen once thereader detects the invented hardware. If the encrypted identificationnumbers do not appropriately match, the foreign user is denied access.

For privacy, individual users are not at risk of exposing their personalinformation, passwords, pins, biometrics, and/or access restrictions toby-standers. Customers do not have to waste time typing passwords orpins to gain access to their personal electronics. Fingernail mounteddevices are waterproof and remain operational for several days ormonths. The invention is able to work in conjunction with mobile phoneor computer applications developed specifically for authenticationpurposes. If removed from the nail or tissue, the invented device ispermanently disabled and all private information is destroyed.

FIG. 10 provides images and experimental results characterizing afingernail mounted silicon CMOS device. Bonding to the surface offingernail is provided by cyanoacrylate providing excellent adhesion.The plots provided demonstrate good electronic performance achieved fora timeframe of about 2.5 months.

FIG. 11 provides images of fingernail authentication device designs. Thepanel to the left shows a fingernail mounted system comprising NFC coilsand NFC chip components provided in a miniaturized format. The panel tothe right shows a fingernail mounted system further comprising an energyharvesting LED indicator also provided in a miniaturized format.

FIG. 12 provides a summary of design information characterizing thecalculated Q factor for NFC fingernail mounted systems. As shown in thisfigure the Q factor is dependent on a number of variables including thethickness and diameter of the NFC coils. High Q factor is beneficial forcommunication with a mobile electronic device, such as a cell phone.

FIG. 13 provides a plot of S21 (dB0) as a function of frequency for aseries of NFC fingernail mounted system designs. The S21 represents thepower transferred between the primary NFC coil from a Samsung cell phoneand the secondary NFC coil from the fingernail mounted NFC system. Thedistance between the primary and secondary coils is set at 5 mm.

FIG. 14 shows a fingernail mounted NFC system for use in conjunctionwith a mouse for authentication of a user to a computer.

FIG. 15 provides a summary of electromagnetic properties as a functionof the radius of curvature. These results demonstrate that thefingernail mounted NFC systems operate at similar ranges regardless offingernail curvature.

FIG. 16 provides an image of a 6″ by 9″ test panel comprising 252 NFCsystems of the invention for tissue mounting applications.

Beneficial aspects of the present fingernail mounted systems of theinvention include:

-   -   Ultrathin, flexible, open architecture (one-size-fits-all        construction)    -   Designs for stable operation under sharp bending    -   Strategies for robust interface adhesion    -   Designs to prevent removal and re-use    -   Materials for operation under extreme conditions    -   Configurations for flexibility in mounting locations    -   Layouts for options in graphics overlays    -   Coils for operation of multiple devices

Example 3—Fingernail Mounted NFC Device for Electronic Payments

The invention provides, for example, fingernail mounted near fieldcommunication (NFC) devices providing a unique platform for mobilepayment and digital wallet service providers. The materials, design, andcircuit integration enable the art of biocompatible NFC technology. Insome embodiments, the built-in NFC technology serves as a digitalreplacement for the magnetic strip found on the back of all debit,credit, and prepaid gift cards. The fingernail-mounted device is able towirelessly communicate with point of sale readers that use NFC antennas.Instead of exchanging cash, debit or credit cards, users have theability to make secure in-store purchases with a single touch or point.Additional payment schemes using the fingernail-mounted device includedevice and pin, a combination of the devices, or a combination of thedevice and a second method for authorization.

In an embodiment, for example, the invention has a devoted chip thatstores encrypted payment information that is unique to each individualdevice. In addition, the chip has transaction-specific security codesthat change after each transaction. The encrypted payment informationand varying security codes are used to process each transaction at timeof purchase. In some embodiments, the payment information is nevershared with merchants or stored on a server. In some embodiments, allfinancial information is stored locally on the consumers' personalmobile devices and/or computers.

In some embodiments, for privacy, the invented hardware does not saveany kind of transaction information. Individual consumers are not atrisk of exposing their name, card number, or security code to retailersor by-standers. Customers do not have to carry their phones, creditcards, and/or cash in order to make electronic payments. In someembodiments, devices are waterproof and remain operational for severaldays or months. The systems of this aspect of the invention are able towork in conjunction with mobile phone applications developedspecifically for payment transactions. In some embodiments, if removedfrom the nail or tissue, the invented device is permanently disabled andall payment information is destroyed.

Example 4—Fingernail Mounted NFC for PersonalIdentification/Authorization

The invention provides, for example, fingernail mounted near fieldcommunication (NFC) devices providing a unique solution for personalidentification in the alcohol distribution, restaurant, bar, education,and/or health-care industries. The materials, design, and circuitintegration enable the art of biocompatible NFC technology. In someembodiments, for example, the built-in NFC technology serves as adigital replacement for drivers' licenses and school identificationcards. The fingernail-mounted devices of this aspect, for example, areable to wirelessly communicate with point of access readers that use NFCantennas. Instead of carrying personal identification cards,fingernail-mounted devices are able to serve as proof of an individual'sidentification and/or store pertinent private information.

In an embodiment, for example, the invention has a devoted chip thatstores an encrypted identification number that is unique to eachindividual device. In addition, the chip has action-specific securitycodes that change after each point of entry. The encryptedidentification numbers can serve as a valid form of identification. Forinstance, “John Smith” (Adult Male Age: 45) uses his fingernail-mounteddevice as proof that is he over the age of 21 to purchase alcohol.

In some embodiments, for privacy, individual users are not at risk ofexposing their name, age, and/or address. In some embodiments, thedevices are waterproof and remain operational for several days ormonths. The systems of this aspect of the invention are able to work inconjunction with mobile phone applications developed specifically forauthentication purposes. In some embodiments, if removed from the nailor tissue, the invented device is permanently disabled and all privateinformation is destroyed.

Example 5—Fingernail Mounted NFC for Key Access/Authentication

The invention provides, for example, fingernail mounted near fieldcommunication (NFC) devices providing a unique solution for key accessto places of residence, offices, hotels, and/or safe industries. Thematerials, design, and circuit integration enable the art ofbiocompatible NFC technology. In some embodiments, for example, thebuilt-in NFC technology serves as a digital replacement for all physicalkeys. The fingernail-mounted devices of this aspect, for example, areable to wirelessly communicate with point of access readers that use NFCantennas. The point of access readers include but are not limited todoor handles, windows, counter-tops, lockers, safes, and/or automobiles.Instead of carrying around keys, key cards, and/or wallets, authorizedfingernail mounted device users are granted access to specific areas,buildings, rooms, and/or automobiles.

In an embodiment, for example, the invention has a devoted chip thatstores an encrypted identification number that is unique to eachindividual device. In addition, the chip has action-specific securitycodes that change after each point of entry. Based off volunteeredpersonal information, the encrypted identification numbers have accessto designated areas. For instance, the invented device is able to unlockhotel room doors.

In some embodiments, for privacy, individual users are not at risk ofexposing their name, room number, and/or access restrictions tothird-party retailers or by-standers. Customers are not required tocarry their cell phones, keys, and/or identification cards to gainaccess authorization. In some embodiments, the devices are waterproofand remain operational for several days or months. The systems of thisaspect of the invention are able to work in conjunction with mobilephone applications developed specifically for authentication purposes.In some embodiments, if removed from the nail or tissue, the inventeddevice is permanently disabled and all private information is destroyed.

Example 6—Finger and Toenail Mounted NFC Device for HospitalMonitoring/Tracking

The invention provides, for example, tissue mounted near fieldcommunication (NFC) devices providing a unique service platform formonitoring and tracking hospital patients. The materials, design, andcircuit integration enable the art of biocompatible NFC technology. Insome embodiments, the built-in NFC technology serves as a digitalreplacement for the hospital identification wristbands and bio-sensingelectrodes using copper wire leads. The fingernail-mounted devices ofthis aspect are able to wirelessly communicate with point of accessreaders that use NFC antennas. The point of access readers include butare not limited to smartphones, door handles, windows, and/orcounter-tops. The invented device gives health-care professionals a wayto electronically track and monitor admitted hospital patients. Thefingernail-mounted or tissue-mounted devices optionally provideadditional bio-sensing modalities that measure temperature, pH levels,glucose, pulse-oximetry, heart rate, respiratory rate, blood pressure,ECG (electrocardiography), EOG (electrooxulography), EEG(electroencephalography), EMG (electromyography), PPG(photoplethysmogram), peripheral capillary oxygen saturation (SpO2),bilirubin level and/or bili light intensity and dose.

In some embodiments, for privacy, the invention has a devoted chip thatstores an encrypted identification number that is unique to eachindividual device. In addition, the chip has action-specific securitycodes that change constantly. The encrypted device number helps keeppatient health-care information private. Clinicians, hospitalmanagement, and insurance providers are the only users with access tothe information. In case of emergency, hospital personnel can quicklylocate missing patients and/or observe patient vital signs.

Individual users are no longer at risk of exposing their name and/orhealth-care information to by-standers. In some embodiments, the devicesare waterproof and remain operational for several days or months. Thesystems of this aspect of the invention are able to work in conjunctionwith mobile phone applications developed specifically for authenticationpurposes. In some embodiments, if removed from the nail or tissue, theinvented device is permanently disabled and all private information isdestroyed.

Example 7—Finger and Toenail Mounted NFC Device for Safe Handling ofHazardous Equipment

The invention provides, for example, tissue mounted near fieldcommunication (NFC) devices providing a unique solution for gun safetyand safe handling of potentially hazardous machinery where safety isrequired. The present invention's materials, design, and circuitintegration enable the art of biocompatible NFC technology. In anembodiment, the built-in NFC technology serves as an additional layer ofsafety and security in operating potentially life-threatening equipment.Life threatening equipment includes but is not limited to guns, saws,and/or cutting machinery. The fingernail-mounted devices of this aspectare able to wirelessly communicate with readers that use NFC antennas.The body designed, wearable NFC technology reduces the misuse ofhazardous equipment through the use of radio frequency identificationsystems. Gun triggers are only able to discharge with the detection ofan authorized fingernail-mounted device. The invented devices of certainembodiments can activate kill switches in industrial or trade cuttingmachinery when the user gets too close to a sharp object.

In an embodiment, the invention has a devoted chip that stores encryptedidentification information that is unique to each individual device. Inaddition, the chip has action-specific security codes that change aftertime of authorization. The encrypted identification information andvarying security codes are used to grant or deny operational access tohazardous equipment.

The systems of this aspect of the invention are able to work inconjunction with mobile applications developed specifically for smartguns and/or hazardous machinery. In some embodiments, the devices arewaterproof and remain operational for several days or months. In someembodiments, if removed from the nail or tissue, the invented device ispermanently disabled.

Example 8—Finger and Toenail Mounted NFC Device for Medication BottleCompliance and Safety

The invention provides, for example, tissue mounted near fieldcommunication (NFC) devices providing a unique solution for medicationbottles and access to medication where compliance and/or safety isrequired. The presented invention's materials, design, and circuitintegration enable the art of biocompatible NFC technology. In anembodiment, the built-in NFC technology serves as an additional layer ofsecurity and/or compliance monitor for medication bottles. Thefingernail-mounted devices of this aspect are able to wirelesslycommunicate with readers that use NFC antennas. The body designed,wearable NFC technology is able to keep track of the amount of times acertain drug bottle is opened and prevents unauthorized individualsaccess to the medication through the use of radio frequencyidentification systems. Pill containers are only able to open with thedetection of an authorized fingernail-mounted device.

In an embodiment, the invention has a devoted chip that stores encryptedidentification information that is unique to each individual device. Inaddition, the chip has action-specific security codes that change aftertime of authorization. The encrypted identification information andvarying security codes are used to grant or deny access to prescribedmedication.

The systems of this aspect of the invention are able to work inconjunction with mobile applications. In some embodiments, the devicesare waterproof and remain operational for several days or months. Insome embodiments, if removed from the nail or tissue, the inventeddevice is permanently disabled.

Example 9—Fingernail Mounted NFC Device for Hospital Hand Washing

The invention provides, for example, tissue mounted near fieldcommunication (NFC) devices, as a unique solution for hospital personnelin monitoring whether or not health-care professionals wash their handsbefore engaging with patients. The present invention's materials,design, and circuit integration enable the art of biocompatible NFCtechnology. In an embodiment, the built-in NFC technology serves as anadditional health monitor and safety precaution. The fingernail-mounteddevices of this aspect are able to wirelessly communicate with readersthat use NFC antennas. The body designed, wearable NFC technologyreduces the risk of health-care associated infections through the use ofradio frequency identification systems. The invented device activates inclose proximity to a reader installed at a sink, hand sanitizer station,and/or room access point. The reader records information from theactivated device such as who washed their hands, at what time, for howlong, and at what temperature. The point of access reader records whowas present in specific locations. Data sets from both readers arecorrelated and used to determine failure to adhere to hand washingprotocols and contaminated areas. The invented device holds the employeeaccountable and ensures a more sanitary environment.

In an embodiment, the invention has a devoted chip that stores encryptedinformation that is unique to each individual device. In addition, thechip has action-specific security codes that change after time ofauthorization. The encrypted information and varying security codes areused to accurately identify individuals. In some embodiments, thedevices are waterproof and remain operational for several days ormonths. In some embodiments, if removed from the nail or tissue, theinvented device is permanently disabled.

Example 10—Fingernail Mounted NFC Device for Gaming, Music-Sharing,Social and Digital Media Platforms

The invention provides, for example, fingernail mounted near fieldcommunication (NFC) devices providing a unique platform for gaming,music-sharing, social and digital media service providers. Thematerials, design, and circuit integration enable the art ofbiocompatible NFC technology. The fingernail-mounted devices of thisaspect are able to wirelessly communicate with smartphones that have NFCcapability. Instead of exchanging phone numbers, email addresses, and/orhome addresses, users have the ability to privately share digitalcontent and/or personal information.

In some embodiments, the invention has a devoted chip that storesencrypted personal identification numbers that are unique to eachindividual device. The encrypted information is a way to privatelydisclose digital content and information. In some embodiments, personalinformation is never shared with merchants or stored on a server withoutuser consent. In some embodiments, all digital information is stored andshared locally on the consumers' personal mobile devices, computers, webpages, and/or gaming systems.

In some embodiments, for privacy, individual consumers are not at riskof exposing personal information or digital content with unauthorizedparties. Customers do not have to carry their phones and/or businesscards to disclose private information. In some embodiments, devices arewaterproof and remain operational for several days or months. Thesystems of this aspect of the invention are able to work in conjunctionwith mobile phone applications developed specifically for media sharingpurposes. In some embodiments, if removed from the nail, the inventeddevice is permanently disabled and all digital content is destroyed.

Example 11—Actuating Tissue Mounted Devices

The invention provides, for example, fingernail-mounted near fieldcommunication (NFC) devices providing a unique platform for consumer,defense, and or intelligence agencies. The materials, design, andcircuit integration enable the art of biocompatible NFC technology. Thefingernail-mounted devices of this aspect are able to wirelesslycommunicate with smartphones and other devices that have NFC capability.Users have the ability to trigger a response that permanently disablesdevice functionality and erases all digital content in the event oftermination of use and or unauthorized possession.

Example 12—Tissue Mounted Devices

The systems and methods of the invention are highly versatile andsupport a broad range of applications. This example illustrates a rangeof different device embodiments supporting many different applications.The following description provides examples showing the broadcapabilities of the present systems. The common components of theexemplified systems include a substrate that has an antenna andinorganic and/or organic electronic components within the system'sdimensions, most of which include but are not limited to a RFID IC thatcan take on various ISO and non ISO compliant forms. The components areconfigured to be used in either an active or passive state depending onthe application. The devices exemplified have dimensions and geometriesallowing for electromagnetic and mechanical form factors which optimallymatch the desired application.

Example 13—Tissue Mounted Devices

The systems and methods of the invention are highly versatile andsupport a broad range of applications. This example illustrates a rangeof different device embodiments supporting many different applications.The following description provides examples showing the broadcapabilities of the present systems. The common components of theexemplified systems include a substrate that has an antenna andinorganic and/or organic electronic components within the system'sdimensions, most of which include but are not limited to a RFID IC thatcan take on various ISO and non ISO compliant forms. The components areconfigured to be used in either an active or passive state depending onthe application. The devices exemplified have dimensions and geometriesallowing for electromagnetic and mechanical form factors which optimallymatch the desired application.

FIG. 17 provides schematic diagrams of various tissue mounted systems ofthe invention.

FIG. 17A illustrates a finger of a person on which a fingernail (faux orother) 1 having a tissue mounted system 2 of the invention attached isbeing placed on the fingernail of a person by means of an adhesive.

FIG. 17B illustrates the head of a person with several different tissuemounted systems attached in different locations using different methods.One or all of the locations shown, and other locations not shown, may beused, but preferred embodiments on the head are illustrated here.Element 1 shows a tissue mounted system attached to the ear whichcontains memory and/or electronic sensors. Element 2 shows a tissuemounted system attached to the tooth using an appropriate adhesive safefor this attachment, the device contains memory and/or electronicsensors. Element 3 shows a tissue mounted system containing electronicsand/or sensors located on or in close proximity of the nose.

FIG. 17C illustrates a finger of a human with a tissue mounted systemcomprising a memory and/or electronic components/sensors mounted usingan adhesive directly to the nail plate. The device 1 is sometimescovered with an additional cover material 2, such as an encapsulation orcover layer.

FIG. 17D shows a person's foot. Located on the foot are three differenttissue mounted systems. Elements 1, 2 are located directly on the nailplate using appropriate adhesive and comprise memory and/orelectronics/sensors. Element 3 shows a tissue mounted system with memoryand/or electronics/sensors located on the toe mounted directly to theskin with an appropriate adhesive.

FIG. 17E illustrates the inside portion of a person's hand with a tissuemounted system 1 mounted on the finger over the fingerprint usingappropriate adhesives. The devices comprise memory and/orelectronics/sensors.

FIG. 17F illustrates a prosthetic socket with a dashed line showing asemitransparent view to expose the tissue mounted system 1 mounted onthe human limb. The tissue mounted systems 1 contain memory and/orelectronics/sensors.

FIG. 18 provides a schematic illustration of a tissue mounted NFC devicemounted on the fingernail for authentication in connection with use of afirearm.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; and non-patent literature documents or other sourcematerial; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used asterms of description and not of limitation, and there is no intention inthe use of such terms and expressions of excluding any equivalents ofthe features shown and described or portions thereof, but it isrecognized that various modifications are possible within the scope ofthe invention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments, exemplary embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims. The specific embodiments provided herein are examplesof useful embodiments of the present invention and it will be apparentto one skilled in the art that the present invention may be carried outusing a large number of variations of the devices, device components,and method steps set forth in the present description. As will beobvious to one of skill in the art, methods and devices useful for thepresent methods can include a large number of optional composition andprocessing elements and steps.

When a group of substituents is disclosed herein, it is understood thatall individual members of that group and all subgroups, including anyisomers, enantiomers, and diastereomers of the group members, aredisclosed separately. When a Markush group or other grouping is usedherein, all individual members of the group and all combinations andsubcombinations possible of the group are intended to be individuallyincluded in the disclosure. When a compound is described herein suchthat a particular isomer, enantiomer or diastereomer of the compound isnot specified, for example, in a formula or in a chemical name, thatdescription is intended to include each isomers and enantiomer of thecompound described individually or in any combination. Additionally,unless otherwise specified, all isotopic variants of compounds disclosedherein are intended to be encompassed by the disclosure. For example, itwill be understood that any one or more hydrogens in a moleculedisclosed can be replaced with deuterium or tritium. Isotopic variantsof a molecule are generally useful as standards in assays for themolecule and in chemical and biological research related to the moleculeor its use. Methods for making such isotopic variants are known in theart. Specific names of compounds are intended to be exemplary, as it isknown that one of ordinary skill in the art can name the same compoundsdifferently.

Many of the molecules disclosed herein contain one or more ionizablegroups [groups from which a proton can be removed (e.g., —COOH) or added(e.g., amines) or which can be quaternized (e.g., amines)]. All possibleionic forms of such molecules and salts thereof are intended to beincluded individually in the disclosure herein. With regard to salts ofthe compounds herein, one of ordinary skill in the art can select fromamong a wide variety of available counterions those that are appropriatefor preparation of salts of this invention for a given application. Inspecific applications, the selection of a given anion or cation forpreparation of a salt may result in increased or decreased solubility ofthat salt.

Every formulation or combination of components described or exemplifiedherein can be used to practice the invention, unless otherwise stated.

Whenever a range is given in the specification, for example, atemperature range, a time range, or a composition or concentrationrange, all intermediate ranges and subranges, as well as all individualvalues included in the ranges given are intended to be included in thedisclosure. It will be understood that any subranges or individualvalues in a range or subrange that are included in the descriptionherein can be excluded from the claims herein.

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art asof their publication or filing date and it is intended that thisinformation can be employed herein, if needed, to exclude specificembodiments that are in the prior art. For example, when compositions ofmatter are claimed, it should be understood that compounds known andavailable in the art prior to Applicant's invention, including compoundsfor which an enabling disclosure is provided in the references citedherein, are not intended to be included in the composition of matterclaims herein.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim. As used herein, “consisting essentially of” doesnot exclude materials or steps that do not materially affect the basicand novel characteristics of the claim. In each instance herein any ofthe terms “comprising”, “consisting essentially of” and “consisting of”may be replaced with either of the other two terms. The inventionillustratively described herein suitably may be practiced in the absenceof any element or elements, limitation or limitations which is notspecifically disclosed herein.

One of ordinary skill in the art will appreciate that startingmaterials, biological materials, reagents, synthetic methods,purification methods, analytical methods, assay methods, and biologicalmethods other than those specifically exemplified can be employed in thepractice of the invention without resort to undue experimentation. Allart-known functional equivalents, of any such materials and methods areintended to be included in this invention. The terms and expressionswhich have been employed are used as terms of description and not oflimitation, and there is no intention in the use of such terms andexpressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the invention claimed.Thus, it should be understood that although the present invention hasbeen specifically disclosed by preferred embodiments and optionalfeatures, modification and variation of the concepts herein disclosedmay be resorted to by those skilled in the art, and that suchmodifications and variations are considered to be within the scope ofthis invention as defined by the appended claims.

We claim:
 1. A tissue mounted electronic system, said system comprising:a substrate having an inner surface and an outer surface; and anelectronic device comprising one or more inorganic components, organiccomponents or a combination of inorganic and organic componentssupported by said outer surface of said substrate; wherein saidelectronic device has a thickness less than or equal to 5 millimetersand has lateral dimensions small enough to provide long-term conformalintegration with said tissue without substantial delamination; andwherein the electronic device comprises one or more near-fieldcommunication coils; and wherein the frequency of each of saidnear-field communication coils changes by less than 50% upon a changefrom a planar configuration to a bent configuration characterized by aradius of curvature selected from the range of 1 mm to 20 mm.
 2. Thesystem of claim 1, wherein said inner surface of said substrate conformsto a curvature of a tissue surface.
 3. The system of claim 1, whereineach of said inorganic or organic components is independently positionedwithin 10 millimeters of an edge of the perimeter of said substrate. 4.The system of claim 1, wherein said tissue mounted electronic system hasa lateral area footprint selected from the range of 1 mm² to 500 mm². 5.The system of claim 1, wherein said tissue mounted electronic system hasan average modulus selected from the range of 10 kPa to 100 GPa.
 6. Thesystem of claim 1, wherein said tissue mounted electronic system has anet bending stiffness selected from the range of 0.1 nN m to 1 N m. 7.The system of claim 1, wherein said tissue mounted electronic system hasan areal mass density selected from the range of 0.1 mg cm⁻² to 100 mgcm⁻².
 8. The system of claim 1, wherein said tissue mounted electronicsystem has an overall maximum thickness less than 0.1 mm and at leastone region having a thickness selected from the range of 0.05 mm to 0.09mm.
 9. The system of claim 1, wherein said inner surface of substratehas an area for establishing said conformal contact with said tissuesurface selected from the range of 1 mm² to 500 mm².
 10. The system ofclaim 1, wherein said substrate has a perforated geometry including aplurality of apertures extending through said substrate, wherein saidapertures allow passage of gas and fluid from said tissue through saidsystem.
 11. The system of claim 1, wherein said apertures provide aporosity of said substrate equal to or greater than 0.01%.
 12. Thesystem of claim 1, wherein said electronic device is a rigid orsemi-rigid device, a flexible electronic device or a stretchableelectronic device.
 13. The system of claim 1, wherein each of said oneor more inorganic or organic components independently comprises one ormore thin films, nanoribbons, microribbons, nanomembranes ormicromembranes.
 14. The system of claim 1, wherein said one or moreinorganic or organic components are independently characterized by acurved geometry selected from the group consisting of: a bent, coiled,interleaved and serpentine geometry.
 15. The system of claim 1, whereinsaid one or more inorganic or organic components are characterized byone or more island and bridge structures.
 16. The system of claim 1,wherein said electronic device comprises one or more actuators or acomponent thereof.
 17. The system of claim 16, wherein said one or moreactuators or component thereof generate electromagnetic radiation,optical radiation, acoustic energy, an electric field, a magnetic field,heat, an RF signal, a voltage, a chemical change or a biological change.18. The system of claim 1, wherein said electronic device comprises oneor more communication systems or a component thereof.
 19. A method ofsensing, actuating or communicating; said method comprising: providing atissue mounted electronic system on a tissue surface; wherein saidtissue mounted electronic system comprises: a substrate having an innersurface and an outer surface; and an electronic device comprising one ormore inorganic components, organic components or a combination ofinorganic and organic components supported by said outer surface of saidsubstrate; wherein said electronic device has a thickness less than orequal to 5 millimeters and has lateral dimensions small enough toprovide long-term conformal integration with said tissue withoutsubstantial delamination; wherein the electronic device comprises one ormore near-field communication coils; wherein the frequency of each ofsaid near-field communication coils changes by less than 50% upon achange from a planar configuration to a bent configuration characterizedby a radius of curvature selected from the range of 1 mm to 20 mm; andsensing, actuating or communicating using said tissue mounted electronicsystem.
 20. A tissue mounted electronic system, said system comprising:a substrate having an inner surface and an outer surface; and anelectronic device comprising one or more inorganic components, organiccomponents or a combination of inorganic and organic componentssupported by said outer surface of said substrate; wherein saidelectronic device has a thickness less than or equal to 5 millimetersand has lateral dimensions small enough to provide long-term conformalintegration with said tissue without substantial delamination; andwherein the electronic device comprises one or more near-fieldcommunication coils; and wherein the effective inductance of each ofsaid near-field communication coils changes by 3% or less upon a changefrom a planar configuration to a bent configuration characterized by aradius of curvature of 5 mm.
 21. The system of claim 1, comprising atleast two near-field communication coils, wherein the near-fieldcommunication coils are separated by a dielectric layer.